US-led strikes on the northern Syrian province of Raqa killed more than 20 Islamic State (IS) jihadists in two positions alone early Tuesday, a monitoring group said.

"More than 20 members of IS were killed in strikes on two of the organisation's positions in Raqa province. The strikes completely destroyed the two positions as well as vehicles stationed there," said the Syrian Observatory for Human Rights, which relies on a broad network of activists and doctors on the ground.