A convoy of US forces armoured vehicles drives near the village of Yalanli, on the western outskirts of the northern Syrian city of Manbij, on March 5, 2017.

A US Marines artillery unit has deployed to Syria in recent days to help local forces speed up efforts to defeat ISIS at Raqqa and the campaign to isolate the city is going “very, very well”, the US-led coalition said on Thursday.

Coalition spokesman US Air Force Colonel John Dorrian said the additional US forces would be working with local partners in Syria – the Syrian Democratic Forces (SDF) and the Syrian Arab Coalition – and would not have a front line role.

The additional deployment comprises a total of 400 US forces – both Marines and Army Rangers. It adds to around 500 US military personnel already in Syria, Dorrian said.

The SDF, which includes the Kurdish YPG militia, is the main US partner in the war against ISIS insurgents in Syria. Since November it has been working with the US-led coalition to encircle Raqqa, ISIS’s main urban bastion in Syria.

This week, the SDF cut the road between Raqqa and the extremists’ stronghold of Deir al-Zor province – the last main road out of the city.

ISIS is also being fought in Syria by the Russian-backed Syrian military, and by Syrian rebel groups fighting under the Free Syrian Army banner with Turkish backing in northern Syria and Jordanian backing in southern Syria.

Dorrian said the effort to isolate Raqqa was “going very, very well” and could be completed in a few weeks. “Then the decision to move in can be made,” he said.

Warplanes kill seven, injure 70 in Syria’s Deir al-Zor

Earlier, air strikes pounded a town in the eastern Syrian province of Deir al-Zor, killing seven civilians and injuring more than 70 others, the Syrian Observatory for Human Rights said.

The Britain-based war monitoring group said two warplanes, believed to be Russian, dropped nearly two dozen bombs on al-Mayadin in the ISIS stronghold of Deir al-Zor.

The strikes hit a school sheltering displaced people, a bakery and residential areas in the town, which lies along the Euphrates river, the Observatory said.

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