A roadside bomb exploded on Friday near a Baghdad security checkpoint manned by members of the government-backed Sahwa militia, killing three people and wounding seven others, police said, according to Reuters. The blast struck a Sahwa checkpoint in the Sunni district of Doura in southern Baghdad, police said. Two of the dead and one of the wounded were Sahwa fighters, a police source said. The Sahwa, recruited mainly from the Sunni Arab minority and including former insurgents who turned against al Qaeda, are credited with helping turn the tide of the sectarian warfare that gripped Iraq in 2006-07. The attack occurred a day after a foiled robbery at a state-run bank in a Shi'ite neighbourhood of southern Baghdad. Two police officers were killed and nine civilians were wounded in that incident, police said. Violence has declined sharply since the peak of the conflict but bombings and other attacks still occur daily. Squabbling politicians have been unable to agree on a coalition government since an inconclusive March 7 parliamentary election, raising tensions as U.S. troops prepare to leave Iraq at the end of next year. Politicians and military officials have said militants are attempting to take advantage of a power vacuum.