A double suicide bombing at Baghdad’s most revered Shia shrine has left at least 60 people dead, the latest in a bombing blitz that has killed and maimed up to 140 people in just 24 hours.

The attack on Friday prayers at the golden-domed Qaddumiyah mosque in northern Baghdad came a day after security forces claimed to have captured one of the leading al-Qaeda figures in Iraq. The two kamikaze attackers blew themselves up in a crowded market just outside the shrine, one of the holiest in Shia Islam.

At least 20 pilgrims from neighbouring Iran were killed in the back-to-back blasts after thronging to Iraq’s Shia holy places. The Qaddumiyah shrine was also attacked by a suicide bomber in Spring 2004, killing scores of people.

Iranian pilgrims made up the vast majority of the 56 victims of a suicide bombing at a restaurant just north of the capital yesterday, which itself came hard on the heels of another attack inside Baghdad that slaughtered almost 28 internally displaced people as they gathered to collect food aid from police officers.

The onslaught has recalled some of the worst days of Iraq’s sectarian bombings, when al-Qaeda sought to ignite civil war by blowing up Shia shrines and market places, killing thousands of people.

Iraqi security chiefs said yesterday they had captured Abu Omar al-Baghdadi, the head of the self-styled Islamic State of Iraq, an al-Qaeda-linked organisation seeking to carve out a Taleban-style enclave in and around the capital. His arrest and killing had been reported on several occasions previously, and US officials have yet to confirm his capture.

The US military has warned that terrorist and insurgent groups will step up their attacks as American troops withdraw from Iraq’s cities by the end of June, according to a schedule agreed on with the Iraqi government. They expect militants to test the strength of Iraq’s new security forces and try to exploit the handover period to stir up still lingering sectarian hatreds.

An investigation in The Times today revealed that widespread abuse of power and corruption among Iraq’s sprawling new security forces are also stoking resentment among the population, stirring people to carry out attacks.

Al-Qaeda in Iraq was largely routed after its local Sunni insurgent allies turned on them and joined so-called Awakening groups, armed, trained and paid by the US military to drive terrorists from their towns. That stunning success has been undermined recently as the US military transfers payment and oversight of the groups to Iraqi control.

The Awakening groups have been repeatedly targeted by militants, and complain they have not received support from the Shia government, which views them with deep distrust. Some Awakening leaders have been arrested on trumped-up charges, their members say.

One of the Awakening leaders was killed last night, along with two other people, in a separate suicide attack in Baquba, close to where the Iranian-filled restaurant was destroyed.

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