IS-held airport captured in Syria

A US-backed Syrian alliance of Kurdish and Arab militias has taken a military airport in northern Syria held by Islamic State, close to the country's largest dam that may be in danger of collapse.

The Syrian Democratic Forces (SDF), which has driven Islamic State from large swathes of northern Syria, said in a statement it had seized the air base.

It has been battling militants near the Tabqa dam and air base west of the Syrian city of Raqqa in an accelerating campaign to capture Islamic State's stronghold.

The Pentagon said last Wednesday it had for the first time airdropped local ground forces behind enemy lines near Tabqa in a move aimed at retaking the major dam.

Islamic State said on its social media channels that Tabqa dam was at risk of collapse because of air strikes and increased water levels.

Islamic State captured the Tabqa Dam, also known as the Euphrates Dam, which is about 40 km upstream from Raqqa and the air base, at the height of its expansion in Syria and Iraq in 2014.

The United Nations warned this year of catastrophic flooding in Syria from the Tabqa dam, which is at risk from high water levels, deliberate sabotage by Islamic State and damage from air strikes.