Assailants struck Shi’ite worshippers in three Iraqi cities on Tuesday, killing at least 39 people in bombings and ambushes during the climax of ceremonies marking Ashoura, the holiest day in the Shi’ite calendar. In apparent retaliation, mortar shells slammed into predominantly Sunni neighbourhoods in Baghdad hours later, killing at least five people and wounding 20, officials said.The surge in violence came a day after Iraq’s army announced it had killed the leader of a cult of messianic Shi’ites called “the Soldiers of Heaven” in a fierce gunbattle aimed at foiling a plot to attack leading Shi’ite clerics and pilgrims in Najaf.The deadliest attack on Tuesday occurred when a suicide bomber blew himself up among a crowd of worshippers entering a Shi’ite mosque, killing 19 people and wounding 54 in Mandalin, a predominantly Shi’ite city northeast of Baghdad and near the Iranian border.To the north, a bomb left in a garbage can exploded about an hour earlier as scores of mostly Shi’ite Kurds were performing rituals commemorating the Islamic sect’s holiest day in the Kurdish city of Khanaqin, also near the Iranian border. At least 13 people were killed and 39 were wounded in that attack, police Major Idriss Mohammed said, adding that most of the victims were Shi’ite Kurds. Gunmen in two cars also opened fire on a bus carrying Shi’ite pilgrims to the capital’s most important Shi’ite mosque at about 10:30 am on Tuesday in Baghdad, killing 7 people and wounding 7 others, police said.The attacks came as millions of Shi’ites commemorated Ashoura, marching in processions and beating themselves bloody in a frenzied show of grief over the 7th-century death of Imam Hussein, grandson of Prophet Muhammad and one of the most revered Shi’ite saints.The US military said Iraqi security forces were sent to Najaf on Sunday after receiving a tip that gunmen were joining pilgrims headed to Najaf to stage a major attack on the holy city coinciding with Ashoura.The fierce 24-hour battle in the area was ultimately won by Iraqi troops supported by US and British jets and American ground forces, but the ability of a splinter group little known in Iraq to rally hundreds of heavily armed fighters was a reminder of the potential for chaos and havoc emerging seemingly out of nowhere. Members of the group, which included women and children, planned to disguise themselves as pilgrims and kill as many leading clerics as possible, said Major General Othman al-Ghanemi, the Iraqi commander in charge of the Najaf region.! Prime Minister Nouri al-Maliki said in remarks published in the Arabic newspaper Al-Hayat on Tuesday that he hopes sectarian militias will be dissolved and the Sunni insurgency ended within six months. “The militias have to end and be transferred to political organisations and any competition with the state in its attempt to bring about security must end,” said al-Maliki, who owes his job in part to the backing of radical Shi’ite cleric Muqtada al-Sadr, leader of the biggest Shi’ite militia, the Mahdi Army.