Russia says targeting IS leaving Syria's Raqa

The defence ministry in Moscow said Russian aviation bombed IS convoys leaving their de-facto capital to the south in the direction of the ancient city of Palmyra on May 25 and overnight from May 29 to May 30.

The second strike destroyed dozens of cars and pickup trucks and killed scores of IS fighters, the ministry claimed in a statement.

"Russian commanders in Syria have warned that any attempt by IS fighters to leave Raqa through the open corridor towards Palmyra will be decisively intercepted," the ministry said.

The latest announcement comes a day after Moscow said it fired four cruise missiles from a submarine and warship in the Mediterranean Sea at IS fighters who had moved close to Palmyra from Raqa.

A US-backed alliance of Kurdish-Arab fighters, the Syrian Democratic Forces, is closing in on Raqa from the north, west and east, but has not yet battled its way to areas south of the city.

Russia has previously suggested that Kurdish forces have wilfully allowed IS to leave the city in the direction of territory controlled by the Syrian government.

Russia has been flying a bombing campaign in Syria since 2015 in support of President Bashar al-Assad, while the US has been leading a coalition mainly targeting IS.

Russian-backed forces retook the UNESCO World Heritage site of Palmyra from IS in March after jihadists ousted them from the oasis city.