A relative of the President has died along with five others in a plane crash at Cork Airport.
Three Northern Ireland businessmen, a Briton, a Spanish pilot and British co-pilot died and six other people were injured - two miraculously walking away from the mangled wreckage - when the 18-seater turboprop crashed on landing in thick fog.
Brendan McAleese, who owned the Central Laundries business in Cookstown, Co Tyrone, was a cousin of Dr Martin McAleese, the husband of President Mary McAleese. He was married with a young family.
Another of those killed was Pat Cullinan, originally from Omagh, Co Tyrone, and a partner in leading accountancy firm KPMG in Belfast, while a third victim was Captain Michael Evans, Deputy Harbour Master in Belfast.
Mrs McAleese and Taoiseach Brian Cowen expressed their shock and sadness at the tragedy - the worst on record at an Irish airport.
"I am especially conscious of the pain being experienced tonight by all of the bereaved as one of the deceased was Brendan McAleese, my husband Martin's cousin," the President said. "His family have lost a fine and loving husband, father, son and brother, and their awful grief is replicated in the lives of all those who lost their loved ones in today's crash.
"No words can ease their pain but I hope they draw some small comfort from knowing that our thoughts and prayers, both here and in homes throughout the country, are with them at this darkest hour.
"To the survivors also we send our heartfelt wishes for a quick and full recovery from the immense trauma they have experienced."
The daily scheduled Manx2 flight took off from George Best Belfast City Airport at 7.50am. It was due to land after 9am but, after two aborted attempts to touch down in thick fog, the Fairchild Metroliner with 10 passengers, pilot and co-pilot on board crashed on a third descent.
Mr Cowen spoke with survivors at Cork University Hospital, including the two walking wounded who suffered bruising and severe shock. "They are in good spirits and they are obviously very grateful for the care they are receiving here at the hospital," he said.