Beirut: Ten people were killed and 20 wounded Saturday in a suicide car bomb attack in Raqa, a former stronghold of the Islamic State group (IS) in north Syria, a rights watchdog said.

The explosion claimed the lives of five civilians and five soldiers of the Syrian Democratic Forces (SDF), a Kurdish-Arab alliance backed by Washington which wrested the city from IS in October 2017, according to the Syrian Observatory for Human Rights (SOHR).

The attack, for which no one has claimed responsibility, was preceded by a bomb explosion that left several people wounded in another part of the city frequently targeted by the Islamic State group, said the SOHR.

"The car bomb attack was targeting an SDF position," SOHR director Rami Abdel Rahmane told AFP. The explosion took place at the al-Naim square where IS had carried out beheadings when it was in control of the city.

On April 9, a double bombing claimed by IS killed 13 people, mostly civilians, in the jihadist group's former bastion.

IS jihadists seized large swathes of Iraq and Syria in 2014, declaring a "caliphate" in areas it controlled.

Several offensives with US-led coalition backing chipped away at the "caliphate" until it was declared eliminated on March 23.

Ambushes and hit-and-run attacks have continued in both countries, with IS jihadists still scattered in the Syrian desert.