Syrian authorities foiled an attempt by the militant Islamic State group (ISIS) to blow up a revered Shia shrine in a Damascus suburb, a source within Syria’s intelligence agency told state news agency SANA on Saturday.

Intelligence and security forces “succeeded in thwarting an attempt by ISIS to carry out a bombing inside the Sayyeda Zainab shrine”, the source said. The interior ministry posted pictures of four men it identified as members of an ISIS cell, arrested in the countryside outside the capital.

It published images of equipment allegedly seized from the suspects, including smartphones, two rifles, what appeared to be three explosive devices and several hand grenades. The photos showed the identity papers of two Lebanese and a Palestinian refugee living in Lebanon.

Iran-backed guards used to be deployed at the gates of the Sayyeda Zainab mausoleum, Syria’s most-visited Shia pilgrimage site.

But they fled shortly before rebels swept into the Syrian capital last month, toppling President Bashar al-Assad. Iran-backed fighters had been key supporters of Assad since the civil war broke out in 2011.

Shia shrines are a frequent target of attacks by ISIS both in Syria and neighbouring Iraq.

ISIS previously targeted the Damascus shrine, claiming a July 2023 bombing that killed at least six people near the mausoleum.

It is the first time the new Damascus authorities said they had foiled an ISIS attack.

IS seized large swathes of Syrian and Iraqi territory in the early years of the civil war, declaring a cross-border “caliphate” in 2014. US-backed Syrian Kurdish forces defeated the proto-state in 2019, but ISIS fighters have maintained a presence in Syria’s vast desert.