U.S.-backed forces in Syria cut road between IS-held Raqqa and Deir al-Zor

Syrian Democratic Forces (SDF) fighters walk with their weapons during an offensive against Islamic State militants in northern Raqqa province, Syria February 8, 2017. REUTERS/Rodi Said

BEIRUT (Reuters) - U.S.-backed Syrian militias cut the last main road out of Islamic State-held Raqqa on Monday, severing the highway between the group's de facto capital and its stronghold of Deir al-Zor province, a militia spokesman said.

The development, confirmed by a British-based organisation that monitors Syria's war, marks a major blow against the Islamic State group that is under intense military pressure in both Syria and Iraq.