The Syrian government forces supported by Russian warplanes have scored new victories in an offensive against one of the last Islamic State (IS) strongholds in the city of Deir al-Zour, the Russian Defense Ministry said Monday.

The Syrian troops operating in the south of the province of Raqqa advanced eight km over the past day and captured two strategically important heights, it said in a statement.

Russian jets have conducted more than 80 combat sorties in support of the offensive, destroying two tanks, three infantry fighting vehicles, more than 10 cross-country vehicles with heavy weapons, the statement said.

More than 70 terrorists were killed or wounded, it said.

The city of Deir al-Zour has been blocked by the IS for several years, with food and other cargoes being delivered to its inhabitants only by air.

The Russian Defense Ministry said the upcoming deblocking of the city will become a "strategic defeat" of IS militants in Syria.

The operations of the Syrian army in the sprawling desert have also extended to the eastern countryside of the central Hama province, where the IS holds key areas there.

The army on Friday drove out the IS militants from their key stronghold of Uqayribat town in the eastern countryside of Hama province in central Syria.

Russia has been participating in operations against the IS and other terrorist groups in Syria since September 2015 at the request of Syrian President Bashar al-Assad.

source: Xinhua