BEIRUT - US Special Forces and experts are setting up an airbase in northeast Syria as part of the battle against the Islamic State group, Syrian military and security sources said Saturday.

They told AFP work was underway to expand an airfield in Rmeilan, in Hasakeh province, from where aircraft used to take off to spray pesticides on crops before Syria’s war started five years ago. A Syrian military source said nearly 100 ‘American experts,’ alongside forces from the anti-IS Kurdish People’s Protection Units had widened the landing strip and refurbished some infrastructure.

‘The airbase will be used for helicopters and cargo planes. Its strip is now 2,700 metres (yards) long and is ready to be used by planes that will transport equipment and ammunition,’ the source added. The Pentagon did not confirm the reports but said the US military had not taken control of any airfield in Syria.

‘There has been no change to the size of mission of the US presence in Syria,’ added US Central Command spokesman Colonel Pat Ryder. ‘That being said, US forces in Syria are consistently looking at ways to increase efficiency for logistics and personnel recovery support,’ he said. At the end of October, US President Barack Obama authorised the deployment of up to 50 special operations troops to Syria to advise local ground forces battling IS.

The military source told AFP that US forces have been working on the Rmeilan airfield ‘for more than three months.’ A security source in northeast Syria said ‘American special forces and advisors are using the Rmeilan airport as a base, from where helicopters are taking off towards the fronts.’ The Britain-based Syrian Observatory for Human Rights said the airstrip has been widened and ‘is nearly ready for us by American planes’.

The US is supporting a Kurdish-Arab alliance called the Syrian Democratic Forces against IS in northern Syria, providing it with air cover as part of a broad coalition battling IS. SDF spokesman Talal Sello denied that US forces had taken over the Rmeilan, describing it as ‘an agricultural airport.’ The US-led coalition began bombing IS targets in Syria in September 2014, expanding their mission from neighbouring Iraq.

Moreover, at least 29 civilians were killed in air strikes suspected to have been carried by Russian warplanes on a village in eastern Syria on Saturday, a monitoring group said. The Syrian Observatory for Human Rights said seven children and one woman were among the dead in the village of Khasham in Syria’s oil-rich Deir Ezzor province.

Controlled by the Islamic State jihadist group, Khasham lies just 20 kilometres (12 miles) southeast of the provincial capital, most of which is now held by IS. The Observatory said the death toll was likely to rise as ‘dozens’ more people were wounded.

The monitor relies on a network of activists on the ground and says it distinguishes between Syrian, Russian and US-led coalition aircraft based on flight patterns, as well as the type of planes and ordnance used. On Friday, air strikes killed at least 44 civilians in Tabiyyah Jazeera, a village adjacent to Khasham. It was unclear if those raids were carried out by Russian or regime warplanes.

But the latest strikes come as Syria’s government pushes to retake territory captured by IS after a fierce offensive by the jihadist group on January 16. The multi-front assault on Deir Ezzor and subsequent fighting has left nearly 500 people dead, according to the Observatory.

While IS holds most of the province, the regime has clung onto parts of the provincial capital, as well as the nearby military airport. The jihadist group has also tightened its siege of the roughly 200,000 people still living inside the city. Russia, a staunch ally of President Bashar al-Assad’s government, began an air campaign in support of Damascus in September.