A reporter for Syrian state television said a preliminary death toll indicated as many as six people may have died. The station broadcast footage of the charred front of a car.

One resident told Reuters he heard a loud blast around 5.30pm, after which security forces sealed off the area.

It was the second attack this week at the shrine. Two people were wounded in a separate blast on Tuesday. It is high season for the shrine as Shiite Muslims flock there to mark the mourning period of Ashura.

Sayeda Zeinab – the granddaughter of the Prophet Mohammad – is venerated by Shiites and her shrine is a site of mass pilgrimage for Shiites from across the world. It has also been a magnet for Shiite militiamen in Syria.

Both Iran and the Tehran-allied Lebanese group Hezbollah have backed Syrian president Bashar al-Assad in the civil war that erupted in 2011.

There was no immediate claim of responsibility for the attack on Thursday. The Islamic State group has claimed previous attacks on the site. One attack in 2017 killed at least 40 people.