The Syrian army has retaken Deir al-Zour, the last major stronghold of so-called Islamic State (IS) in Syria, state TV says.

"The city is completely liberated from terrorism," the state TV report said.

Other reports said the Syrian army and its allies were clearing the last pockets of resistance from IS.

IS had held most of the city since 2014. It was of strategic importance to IS because of its proximity to the border with Iraq.