The Islamic State jihadist group expelled Syrian regime troops Monday from the northern province of Raqa in a counter-offensive that killed 40 regime forces in 24 hours, a monitoring group said.

The Syrian Observatory for Human Rights said the jihadists' attack was launched on Sunday following a regime offensive into the IS stronghold of Raqa on June 3 that advanced around 20 kilometres (12 miles) to capture the town of Tabqa.