Islamic State claimed a triple suicide attack on Thursday evening near a Shi'ite mausoleum north of Baghdad, which killed at least 35 people and wounded 60 others, according to Iraqi security sources. The attack on the Mausoleum of Sayid Mohammed bin Ali al-Hadi reignited fears of an escalation of the sectarian strife between Iraq's Shi'ites and Sunnis.

The Shi'ite form a majority in Iraq but Sunnis are predominant in northern and western provinces, including Salahuddin where the mausoleum is located.

Prominent Shi'ite cleric Moqtada al-Sadr ordered his militia, the Peace Brigade, to deploy around the mausoleum, near Balad, about 93 kilometres (58 miles) north of Baghdad.

Sadr's militia is also deployed in Samarra, a nearby city that houses the shrine of Imam Ali al-Hadi, the father of Sayid Mohammed whose mausoleum was attacked on Thursday.

A 2006 bombing destroyed the golden dome of the shrine of Ali al-Hadi and his other son, Imam Hasan al-Askari, setting off a wave of sectarian violence akin to a civil war.

Pictures posted on social media showed a fire burning in the market located at the entrance of the Sayid Mohammed mausoleum. It was not clear if the site itself was damaged.