Forces loyal to Syrian President Bashar al-Assad have attacked the last rebel stronghold in the capital Damascus.

Dozens of tanks and armoured vehicles entered the southern district of Tadamon on Friday, with activists saying most of the area is back under government control.

The army had been trying to enter Tadamon for more than a week but have previously been pushed back by fierce resistance from rebels.

One resident said: "Thousands of soldiers have entered the neighbourhood, they are conducting house-to-house raids."

The violence came within hours of former UN Secretary-General Kofi Annan quitting as international peace envoy for Syria.

A senior UN official said a long-expected government attack on Aleppo is imminent following a build-up of reinforcements.

Rebels poured into Syria's largest city last month after being largely driven from the capital.

The fighting in Syria's two main cities has intensified over the past three weeks.