Syrian troops and rebels are fighting some of the fiercest battles in the northern city of Aleppo, activists have said.
The clashes are part of a new push by the rebels to drive regime forces out of Syria's largest city and commercial capital after weeks of stalemate.
Aleppo-based activist Baraa al-Halabi said some of the heaviest battles are taking place in a predominantly Kurdish neighbourhood.
The major rebel group in the city - the Tawhid Brigade - said on its Facebook page that its members have entered the Sheikh Maksoud neighbourhood to fight pro-government Kurdish gunmen.
Meanwhile, state-run Syrian TV said government troops repelled an attack on the neighbourhood with the help of its residents.
Aleppo was once a bastion of support for president Bashar Assad.