BAGHDAD  - Three women bombers blew themselves up on Monday in a crowd of Shia pilgrims in Baghdad, one of a string of attacks in Iraq that killed at least 56 people, undermining hopes of a drop in violence. Scores of people were also wounded in the attacks, which follow a relative lull in the sectarian violence that has ravaged the country since February 2006, when insurgents blew up a Shia mosque in the central city of Samarra. The triple attack in Baghdad killed at least 25 pilgrims as they headed to a holy shrine for a major religious ceremony that has been marred by bloodshed in the past, security officials said. Another 22 people were killed in a suicide bombing during a protest rally in the northern oil city of Kirkuk, and gunfire in a panicked stampede that followed, local officials said. Among the dead in the Baghdad bombings were women and children, security and hospital officials told AFP, adding that about 70 other people were wounded. The bombers struck in the Karrada district of central Baghdad as pilgrims were making their way on foot towards Kadhimiyah in the north of the Iraqi capital, site of a Shia festival Tuesday. "At least 25 people were killed and more than 70 were wounded in three suicide attacks, probably by females suicide bombers," a police official said. Pilgrims from around the country are flocking to the Iraqi capital to mourn the revered imam who died 12 centuries ago, prompting authorities to step up security amid concerns over attacks.  Systematic violence - suicide bombings and sectarian killings - have dropped sharply in the capital since a peak in 2006, but Iraqi police are worried about a wave of attacks in the city of six million people. Major General Kassam Atta, spokesman for city security, told reporters that his force had information regarding the possibility of attacks targeting pilgrims during this year's festival. "We ask people to help in all ways with our security forces," Atta said, adding that up to one million people were expected. Checks have been particularly stringent amid what appears to be growing trend of using women in insurgent bombings, which have claimed hundreds of lives across the volatile country. The attack in Kirkuk targeted a crowd of people who were protesting a controversial provincial election law, police said. "The suicide bomber detonated his explosives amid the crowd, causing a stampede which prompted guards to open fire," officials said. "More people then responded to the gunfire with more shooting. The result of all this was 22 people killed and 120 injured." Kirkuk is often the scene of communal tensions among Kurds, Arabs and Turkmens, and the latest violence was sparked by protests over the controversial legislation for planned provincial elections. The draft is currently being reviewed by the Iraqi parliament but many Kurdish and Shiite ministers are opposed to the bill. Kurds in particular are worried that the law will fail to address issues relating to how the provincial council of Kirkuk should be constituted. The question is important to them because it could affect ownership of the northern province's oil resources, claimed by both Arabs and Kurds. Another three men and a woman were killed in a roadside bombing near Baquba, north of Baghdad, police said.