Syrian government forces push into Raqqa towards IS-controlled dam

Syrian troops pushed into the Islamic State (IS) group's bastion province Raqqa on Saturday for the first time since 2014, in an advance towards the country's largest dam, a British-based monitoring group said on Saturday.

The Tabqa dam on the Euphrates River, 40 kilometres upstream from Raqqa city, is also the target of a separate offensive launched by US-backed Kurdish-led forces advancing from the north late last month.

"Regime troops backed by Russian air strikes and Russian-trained militia entered Raqa province on Saturday morning for the first time since August 2014," Syrian Observatory for Human Rights director Rami Abdel Rahman told the AFP news agency.

The lightning advance from the southwest brought government troops to within less than 40 kilometres of Tabqa, which is also the site of an airbase, Abdel Rahman said.

"It seems there has been an undeclared coordination between Washington and Moscow," he added, referring to the pincer movement by the two governments' respective Syria allies.

At least 26 militants and nine government troops and militia were killed in the advance, according to the observatory, which relies on reports from medics and activists on the ground.

Tabqa dam has a huge reservoir named Lake Assad after Syrian President Bashar al-Assad's late father and predecessor Hafez.

When IS overran the area in 2014, it summarily executed 160 captured government troops.

IS is currently facing counter-attacks on multiple fronts.

Arab and Kurdish fighters backed by Washington have launched an assault on the strategic Manbij pocket further up the Euphrates on the Turkish border, regarded as a key entry point for foreign fighters joining IS.

Hundreds of kilometres downstream in neighbouring Iraq, government forces backed by Shia militias have launched an assault on the emblematic IS bastion of Fallujah, while Iraqi Kurdish Peshmerga fighters have also advanced into previously IS-held territory in anticipation of an advance on the major city of Mosul.