Twin car bombs targeted a meeting of Sunni tribal leaders, killing as many as 22 people in the latest attack against US allies who have turned against al-Qaida in Iraq. The attackers managed to penetrate heavy security Monday to leave bomb-rigged cars near a Baghdad compound hosting chieftains from the western Anbar province, where the so-called Awakening Council movement against al-Qaida emerged last year. The blasts were also near the offices of one of Iraq's most powerful Shi'ite politicians, Abdul-Aziz al-Hakim. But Iraqi authorities said the apparent target was the Sunni tribal heads. Insurgents - either led or inspired by al-Qaida - have stepped up assaults against fellow Sunnis who are credited with helping drive out extremists from key parts of Baghdad and surrounding areas. Sheik Ali Hatem al-Sulaiman, deputy chief of Anbar province's biggest Sunni tribe and a leading member of the Anbar Awakening Council, said six of their bodyguards were among those killed. At least 20 were wounded, he said. He blamed al-Qaida in Iraq, which has increasingly targeted Sunnis who have turned against it. The Anbar sheiks often meet in Baghdad. They also have lobbied parliament in recent days over stalled draft legislation that would set a date for provincial elections. "Al-Qaida and those who assist al-Qaida are targeting our offices. We ask the government not to diminish our role," al-Sulaiman told The Associated Press, insisting on a tribal right to revenge. "It has become a reprisal issue now and we don't want the government or the US forces to interfere," he said. "It is an open war against those criminals, and we will fight in our own way." A dense cloud of black smoke filled the air as firefighters hosed down dozens of charred vehicles. The blasts ripped a crater two yards wide in the asphalt. The Iraqi military spokesman said an explosives-laden minibus and a sedan blew up nearly simultaneously - the first near a gas station and the second within minutes near the tribal chiefs meeting. Iraqi police and hospital officials, speaking on condition of anonymity because they were not authorized to release the information, said at least 22 people were killed and 42 wounded. The office of Iraq's chief military spokesman, Brig. Gen. Qassim al-Moussawi, put the casualty toll at 14 killed and 45 wounded. The US military, meanwhile, pressed forward with its campaign against Shi'ite extremists who have refused to follow a cease-fire ordered by cleric Muqtada al-Sadr, who controls the most powerful Shi'ite militia faction. The cease-fire expires later this month. American soldiers captured a suspected Shi'ite militia commander and one other suspect Monday in the latest of several days of raids in Shi'ite holy cities south of the capital. The suspect was allegedly involved in coordinating weapons shipments and planning attacks on US and Iraqi forces in the Iraqi provinces of Wasit, Babil and Najaf, the military said. It did not give details on the second suspect. Sadrist lawmaker Ahmed al-Masaoudi, however, insisted the two men arrested in Hillah, about 60 miles south of Baghdad, were one of his guards and his brother, and he demanded their immediate release. The US CBS television network, meanwhile, reported that two of its journalists had gone missing in the predominantly Shi'ite southern city of Basra. CBS did not name the journalists but said all efforts were under way to find them and requested "that others do not speculate on the identities of those involved." Basra, Iraq's second-largest city, has seen fierce fighting between rival Shi'ite militias as part of a power struggle in the oil-rich south. The British military turned over responsibility for the province to the Iraqis in December but maintains forces near the city, about 340 miles southeast of Baghdad. Also Monday, the US military announced the death of an American soldier, killed in a roadside bombing a day earlier. At least 3,960 American troops have died in Iraq since the war started in March 2003, according to an Associated Press count.