The Queen has said she was "saddened" by an accident which left six people dead, including three members of one family, when a bin lorry careered out of control in a packed city centre.
Five females and one male were killed when a bin lorry careered out of control in Glasgow city centre, police have said.
A further 10 people were injured when the truck mounted a pavement before crashing into the side of a hotel yesterday afternoon.
The accident happened in George Square, which was packed with Christmas shoppers and families enjoying the annual winter carnival.
She said she and the Duke of Edinburgh sent their "thoughts and prayers" to the families affected by the tragedy in Glasgow's George Square.
Jack Sweeney (68), his wife Lorraine (69), and granddaughter Erin McQuade(18), were among those killed yesterday after the council vehicle drove through a street full of Christmas shoppers.
Gillian Ewing, 52, from Edinburgh, Stephenie Tait, 29, and Jacqueline Morton, 51, both of Glasgow, also died.
Ten people were injured in the crash, with six people, including the driver of the bin lorry, still being treated in Glasgow hospitals.
Four patients remain in Glasgow Royal Infirmary, although one is expected to be discharged later today.
Another is described as being in a critical condition, one patient is serious but stable, and one patient is stable.
Mr Sweeney was a former president of Bramalea Celtic supporters club in Canada.
A statement posted on the Bramalea CeItic supporters club Facebook page said: ''It is with great shock and sadness we share with you, our friend and past president Jack Sweeney, his wife Lorraine and granddaughter Erin were victims of today's tragedy in Glasgow.
''Our thoughts and prayers go to the family and friends of the Sweeney family.''
Miss McQuade worked at the luxury Cameron House Hotel on the banks of Loch Lomond.
The hotel said in a statement: ''We are saddened to hear we have lost one of our brightest and dedicated members of housekeeping staff, Erin McQuade.
''We want to offer our deepest condolences and sympathies to the family of Erin and to all those who have been affected by the tragic events at George Square yesterday.''
Newsflash: Refuse truck crashes into Millenium Hotel in George Square in Glasgow. Will cause traffic probs. pic.twitter.com/qtq0psdxyg— Calgacus MacAndrews (@CalgacusMacA) December 22, 2014
Relative John Sweeney described himself as ''feeling heartbroken'' on Facebook.
He wrote: ''No words can describe the pain. RIP Jack, Lorraine and Erin. Thoughts and prayers go out to the other families that lost loved ones as well.''
Ms Tait was a primary school teacher at St Philomena's Primary in Glasgow.
Head teacher Catherine Gallagher said the "entire school community is deeply saddened by this tragic news".
She added: "Stephenie was an excellent young teacher, dedicated to the children. Our thoughts and prayers are with her family and friends at this time.
"We will be supporting colleagues in every way possible. Stephenie made a wonderful contribution to the life of St Philomena's. She will be sadly missed by both pupils and staff."
Lord Provost of Glasgow Sadie Docherty received a message of condolence from the Queen to all the people of city.
The Queen said: "Prince Philip and I were saddened by the news of the tragic accident in Glasgow yesterday.
"Our thoughts and prayers go to the families of those who have lost loved ones and to those who have been injured.
"This sad event is made even more difficult as it comes at Christmas time. I send my condolences to all the people of Glasgow."
Police Scotland said in a statement: "As a result of the collision, six people died and 10 people were injured, including the driver.
"Seven casualties were taken to hospital by the ambulance service, two walked in to hospital and one was treated at the scene. Four have since been discharged.
"There are currently six people in hospital being treated for their injuries. Two have been moved to the Intensive Therapy Unit for further monitoring.
"The deceased includes one male and five females."
Police refused to comment on reports that three members of the same family are feared to be among the victims.
Witnesses described bodies lying in the road after the tragedy in Glasgow city centre which is being treated by authorities as a major incident.
A Police Scotland statement said: "Regarding a major road incident in George Square, Glasgow, please note that we can confirm that six people have been fatally injured as a result."
Police Scotland have yet to confirm the identities of any of those killed when the truck careered through George Square yesterday afternoon.
But posts on social media identified grandparents Jack and Lorraine Sweeney, and their granddaughter Erin McQuade, among those to have lost their lives.
It is believed Mr Sweeney had previously lived in Ontario, in the east of Canada, where he was president of a branch of the Celtic FC supporters' club.
A statement on the Bramalea Celtic Club's Facebook page read: "It is with great shock and sadness we share with you our friend and past president Jack Sweeney, his wife Lorraine and granddaughter Erin were victims of today's tragedy in Glasgow.
"Our thoughts and prayers go to the family and friends of the Sweeney family."
Three other females were also killed and 10 people were injured, six of whom remain in hospitals around the city.
Relative John Sweeney described himself as "feeling heartbroken" on Facebook.
He wrote: "No words can describe the pain. R.I.P. Jack, Lorraine and Erin. Thoughts and prayers go out to the other families that lost loved ones as well."
On Tuesday a special service was held at the nearby St George's Tron Parish Church.
The Rev Stuart Smith, moderator of Glasgow Presbytery of the Church of Scotland, said the circumstances of the crash were "more sudden and shocking than we could have imagined possible if it wasn't for the evidence right here in front of us".
The service, which was attended by First Minister Nicola Sturgeon and Glasgow City Council leader Gordon Matheson, began with the carol In The Bleak Midwinter.
Mr Smith said: "In just a few minutes yesterday afternoon a scene of celebration and festive lights in George Square turned to devastation and despair. A bleak midwinter and darkness indeed.
"Yet almost immediately first volunteers, passers-by and then our emergency services appeared on the scene, bringing compassion and skill and dedication and light into the darkness."
He said the tragic events in the city centre had "affected us all and brought us all here together as one".
Mr Smith added: "It has been well said that 'people make Glasgow' but yesterday Glasgow lost some of her people and others were terribly injured.
"Each death and each injury that took place yesterday afternoon is, of course, a personal tragedy. But it is also Glasgow who has lost her people and as a city we feel it and suffer together."
The crash happened just over a year after a police helicopter crashed into the Clutha Bar in Glasgow, killing 10 people.
Mr Smith said the city then "found in the midst of tragedy a strength that has not let us down".
He told the congregation that they had come together "side by side and arm in arm as a city united in grief".
A teenager has been arrested after allegedly posting an offensive message on Twitter regarding the fatal bin lorry crash in Glasgow.
The 19-year-old, believed to be Ross Loraine, from Sunderland, handed himself in to police yesterday evening after a number of complaints were made about the tweet.
He is alleged to have written: "So a bin lorry has crashed into 100 people in Glasgow eh, probably the most trash its ever picked up in one day that."
Northumbria Police said he was arrested on suspicion of making a malicious communication and had been bailed while they made further inquiries into the incident.
Superintendent Stewart Carle said the lorry hit several pedestrians as it careered along the road.
He said: "It's difficult for all the emergency services but particularly for those people who have been in Glasgow today shopping and getting ready for Christmas.
"There will be a lot of distressed people and certainly the city will need to come round those people that have been traumatised by the incident."
Mr Carle said that at "about 2.30pm a Glasgow City Council bin lorry was travelling north on Queen Street outside the Gallery of Modern Art when it was in a collision with a pedestrian".
"The bin lorry then has continued north on Queen Street, it would appear to have gone up on the footway and there have been a number of other pedestrians it has collided with."
Eyewitnesses described bodies lying in the road after the accident which happened as the city centre was crowded with Christmas shoppers.
In an earlier statement Police Scotland said: "A Glasgow City Council bin lorry was travelling north on Queen Street when it appeared to strike pedestrians outside the Gallery of Modern Art (GOMA) before continuing to travel towards George Square, when it crashed at the Millennium Hotel on Queen Street at George Square.
"There have been a number of fatalities and people injured.
"All roads in the surrounding area are closed and people are advised to stay away from George Square and make alternative travel arrangements."
It added: "If you have any concerns relating to this incident call Police Scotland on 01786 289 070."
Superintendent Stewart Carle of Police Scotland said at the scene that the lorry hit several pedestrians as it careered along the road.
He sought to reassure people saying: "It's a road traffic accident, nothing more sinister."
Police Scotland Assistant Chief Constable Wayne Mawson, local policing commander for the west, said: "This is a tragic incident which has taken place at a very busy time in the centre of our city. Please be assured my officers and other members of the emergency services will do everything they can to respond to this collision.
"We have set up a helpline for anyone who believes a friend or relative may have been involved in this incident. The number is 01786 289070. However, due to the volume of calls that we are receiving, it would be helpful if anyone who was in Glasgow city centre today can call home to let their loved ones and friends know that they are safe.
"The safety of the people of Glasgow is our priority and the emergency services will continue to work together to establish the exact circumstances."
Prime Minister David Cameron said: "I'm being kept fully briefed on the major incident in Glasgow. My thoughts are with the families of those involved and the emergency services."
Scottish Secretary Alistair Carmichael said: "I share Scotland's deep shock at the horrible events in Glasgow this afternoon.
"On the eve of the festive period, these are unimaginable scenes in one of the busiest parts of our largest city.
"My thoughts are with the bereaved, the emergency services dealing with the aftermath and everyone affected by this terrible incident."
Labour leader Ed Miliband said: "Terrible news from Glasgow - my thoughts are with all those affected by this horrific accident."
Reports suggested the lorry first struck pedestrians queuing at the Gallery of Modern Art (GoMA), a short distance from George Square.
A spokesman at the venue said the museum had not been closed, but could not add any further details.
A message on its Twitter page read: "Due to an incident at George Square, access to GoMA restricted. Road closures in place. Our thoughts are with all those affected."
Describing the scene on Twitter, Brett Molloy tweeted: "Whole of George square is shut off, bodies on the road. Scary man.
"Horrible, horrible scenes. Even worse at this time of the year.
"City centre is an eerie, eerie place right now."
Kevin @km747 tweeted: "Horrific scenes in George Square. Here now and it's clear to say lives have been lost."
Restaurant owner George Smith told the BBC he had heard that the bin lorry driver had suffered a heart attack and the vehicle had careered along the street before hitting the pedestrians outside the Millennium Hotel.
He said that the emergency services were on the scene within minutes, adding: "It's really, really sad."
The Scottish Fire Service tweeted: "Firefighters are in attendance at a serious incident in Queen Street, Glasgow. Our crews are working alongside other emergency responders."
Comedian Janey Godley tweeted: "Utter horrific carnage, people on ground getting triage."
John Maclennan said: "Seeing injuries in Royal Exchange Square, bin lorry ran all the way up Queen Street into #georgesquare, awful."
Witness Janey Godley told the BBC News Channel that people were "getting CPR (cardiopulmonary resuscitation) on the ground" when she arrived in the square.
"I think I was there just as the ambulances arrived, because there was stuff strewn, debris strewn, all over the street, Christmas shopping all over the street," she said.
Ms Godley said she saw three people being treated by emergency crews.
She said: "People were being worked on, people were fighting for their lives on the pavement as shoppers were standing.
"People just like me had arrived on the most shocking scene they ever wanted to see this Christmas. George Square is a square with a fairground and an ice rink and Santa and the tree and everything."
Ms Godley added: "It was the most horrible thing to watch all the ambulances and the people in the street, and yet the fairground in the background, and people just in shock."
She said it was "an awful tragic thing to happen at this time of year".
Source Independent additional reporting PA