Turkish prime minister Recep Tayyip Erdogan said Syrian president Bashar al-Assad should look to Libya to see what happens to leaders who rule through violence against their own people.
"Without spilling any more blood, without causing any more injustice, for the sake of peace for the people, the country and the region, finally step down," Mr Erdogan told a meeting of his ruling AK Party.
Turkey can't ignore violence and cruelty in a neighbour and its concern doesn't mean "interference, or calls for an external intervention," Mr Erdogan said.
Earlier today Syrian forces killed four villagers in the central province of Homs in an escalating crackdown on the most defiant centre of opposition to Dr Assad in an eight-month-old uprising, activists said.
Two children, aged about 10, were among those killed when tanks fired at villagers in the main street of Tal Dao in the Houla region, 22km northwest of the Homs, the provincial capital, who had ignored a curfew announced by loudspeakers from tanks, they said.
Agencies