A woman suicide bomber walking among Shia pilgrims in Baghdad detonated an explosives belt on Monday killing at least 46 people and wounding more than 122, officials said.

The bombing was the first major strike this year against pilgrims making their way to the southern city of Karbala to mark a Shia holy day. It came as security official warned of a possible increase in attacks by insurgents using new tactics to bypass bomb-detection methods.

The bombing raises fears of an escalation of attacks as hundreds of thousands of Shias head by Friday to the southern holy city of Karbala to mark the end of 40 days of mourning following the anniversary of the death Imam Hussein, a revered Shia figure. The bomber hid the explosives underneath an abaya — a black cloak worn from head to toe by women — as she joined a group of pilgrims on the outskirts of Baghdad’s Shia-dominated neighbourhood of Shaab, said Major-General Qassim Al-Moussawi, Baghdad’s top military spokesman.

The bomber set off the blast as she lined up with other women to be searched by women security guards at a security checkpoint just inside a rest tent.

After clearing the security check, the women pilgrims were served water and sherbet, a police official said.

Another police official said 46 people were killed, including at least five women and six children, and 122 were wounded. All the officials spoke on condition of anonymity because they were not authorized to talk to the media.

Despite an overall decline in violence in Iraq, Al-Qaeda and other Sunni extremists have routinely targeted pilgrims in an attempt to stoke sectarian strife and weaken the Shia-dominated government.

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