Over 30 people have been killed and more than 60 others wounded in a car bomb attack on a Shi’ite mausoleum north of Baghdad, security sources said, according to Reuters. Several gunmen reportedly stormed the site, opening fire on Eid al-Fitr festival pilgrims.

A suicide car bomb tore through the external gate of the Mausoleum of Sayid Mohammed bin Ali al-Hadi, a Shi’ite holy site located 93 kilometers (58 miles) north of Baghdad.

Reuters news agency cites local security sources as saying that after the blast, several gunmen stormed the site and opened fire on worshipers celebrating the festival of Eid al-Fitr.

The unconfirmed death toll has reportedly climbed from an initially reported 20 people to at least 35. The number of the injured, which had originally been reported as standing at 50 has now reached at least 65, according to local media.

Unconfirmed reports also suggest that three suicide bombers have been arrested and two undetonated belts have been found.

Stepped-up security forces have allegedly blocked all the exits at the site.

The attack in Balad comes just days after a refrigerator truck bomb in a Shiite district in Baghdad killed at least 292 people on July 3. Islamic State (IS, formerly ISIS/ISIL) claimed responsibility for what has become Baghdad’s deadliest single attack this year.

There was no immediate claim of responsibility for the bombing in Balad, but ISIS has carried out multiple attacks targeting Shi’ites in Iraq in recent months.