Five US troops were killed in separate attacks this weekend, including three in a single roadside bombing in Baghdad, the military said Monday, pushing the death toll past 100 in the deadliest month so far this year. Two attacks occurred in eastern Baghdad, a predominantly Shiite area where American and Iraqi forces have stepped up their activities as part of a security crackdown that began on Feb. 14 to quell the sectarian violence. A Marine also was killed in Anbar province, a Sunni insurgent stronghold west of the capital. In violence Monday, a suicide car bomber apparently targeting an Interior Ministry convoy struck an Iraqi checkpoint near a busy square in the predominantly Sunni area of Harthiyah in western Baghdad, killing four people and wounding 10, police said. The bomber detonated his payload, causing part of the road to buckle, as he emerged from an underpass and was heading toward the checkpoint being manned by Interior Ministry commandos. Those killed included two commandos and two civilians. The violence occurred despite stringent security measures during the security crackdown now in its 11th week. On Sunday, Iran agreed to join the US and other countries at a conference on Iraq this week, raising hopes the government in Teheran would help stabilize its violent neighbor and stem the flow of guns and bombs over the border. Senior Iranian envoy Ali Larijani flew to Baghdad on Sunday for talks with al-Maliki and other senior Iraqi officials ahead of this week's meetings in Egypt - the highest-ranking Iranian official to visit Iraq since the collapse of Saddam Hussein's regime in 2003. Earlier this month, US military spokesman Maj. Gen. William Caldwell said Iranian intelligence operatives have been training Iraqi fighters inside Iran on how to use and assemble deadly roadside bombs known as EFPs, or explosively formed penetrators. He said Iranian support extended to Sunnis as well as Shiites in Iraq, showing reporters photographs of what he said were Iranian-made mortar rounds, RPG rounds and rockets that were found recently in a Sunni neighborhood of Baghdad. The killings of the Americans came as US troops have been increasingly deployed on the streets of Baghdad and housed with Iraqi troops in joint security stations away from their heavily fortified bases, raising their vulnerability to attacks. The roadside bomb killed three soldiers and wounded another while they were on a combat patrol Sunday in eastern Baghdad, the military said, without providing more details. An Iraqi interpreter also was killed in the attack. Another soldier was killed by small arms fire in eastern Baghdad on Saturday, and a Marine was killed in fighting Sunday in Anbar, according to separate statements. The deaths raised to at least 104 American troops who have died in Iraq as April draws to a close, making it the deadliest month since December, when 112 Americans died. The US monthly death toll has topped 100 five other times since the Iraq war began in March 2003, according to an Associated Press count based on military figures. At least 3,351 members of the US military have died since the war started, according to the AP count. US President George W. Bush has committed some 30,000 extra American troops to the security operation in Baghdad, but he also is facing legislation by the Democratic-led Congress calling for the Americans to begin withdrawing from Iraq by Oct. 1. Bush has promised to veto the measure. It also has been the deadliest month for British forces in Iraq since the first month of the war. The 11 British troops deaths reported this month is surpassed only by 27 who died in March 2003, reflecting increasing violence in southern Iraq where they are based, particularly among Shiite groups vying for influence as Britain prepares to reduce its forces. In the southern city of Basra, some five people were killed in an explosion Sunday. Iraqi police initially reported that it was a car bomb, but the British military said it appeared that the blast accidentally occurred while explosives and weapons were being moved. The area is mainly Shiite and rarely sees the car bombs usually blamed on Sunni insurgents, although rival Shiite militias frequently clash and stage attacks. The US military said Monday that a joint American-Iraqi raid the day before was aimed at capturing "high-value individuals" in the north Baghdad heavily Shiite district of Kazimiyah and left one Iraqi soldier and eight gunmen dead. Iraqi police officers in the area said the raid was targeting a local office of radical Shiite cleric Muqtada al-Sadr and that the guards clashed with the forces. The military statement said eight individuals were detained and later turned over to the Iraqi security forces. It added that none of the targeted individuals were captured as a result of this operation and all detained individuals were later released. In northern Iraq, a parked car bomb struck a police patrol in the Raas al-Jada, a mainly Sunni Arab area in the northern city of Mosul, killing one policeman and wounding two others, police Brig. Gen. Mohammed Idan al-Jubouri said. The attack occurred at 8 a.m., about four hours after some 50 gunmen attacked a police station in the same area, prompting a firefight and clashes as police chased the gunmen through the narrow streets. Four of the gunmen were killed and two others detained, while one policeman was wounded, police said. Police also cordoned off the area and blocked five bridges after four mortar rounds landed on the police command headquarters elsewhere in Mosul, causing no damages, said Brig. Saeed Ahmed al-Jubouri, the media director for the provincial police.