Syria's army is in complete control of the capital and its outskirts for the first time since 2012 after ousting the Islamic State group from a last pocket of resistance.

It marked a major milestone in the protracted war, which began in 2011 and saw parts of Damascus fall to armed rebels the following year.

But in recent months, President Bashar al-Assad has used a blend of military pressure and negotiated withdrawals to steadily flush rebels out of territory around Damascus.

A small IS holdout remained in the capital's south.

Troops and allied Palestinian militia launched an offensive last month to recapture the area covering the Palestinian camp of Yarmuk and adjacent districts of Qadam, Tadamun and Hajar al-Aswad.

On Monday, the army declared it had ousted IS from that zone, sealing its control of the capital.

'The Syrian army announces today that Damascus, its outskirts and surrounding towns are completely secure,' it said in a statement.

'The wheel of our progress on the battlefield will not stop until all Syrian land is purified,' it said.   -- Agencies