(Adds detail on oil law) By Ahmed Rasheed and Ibon Villelabeitia BAGHDAD, Feb 26 (Reuters) - Iraq's Shi'ite vice president and a cabinet minister were wounded in an apparent assassination attempt on Monday when a bomb killed six people at a ministry in Baghdad where they were attending an official ceremony. While militants defied the security crackdown in Baghdad, the cabinet took a major step to resolve political divisions by endorsing a draft oil law and sending it to parliament for approval, Deputy Prime Minister Barham Salih told Reuters. Passing a law that regulates how Iraq's vast oil wealth will be shared between warring ethnic and sectarian communities has been a top demand of Washington to keep its support for Shi'ite Prime Minister Nuri al-Maliki's government. Police said Public Works Minister Riad Ghareeb, another Shi'ite, was seriously wounded when a bomb hidden at a ministry's meeting hall exploded. Aides to Vice President Adel Abdul-Mahdi said he escaped with light shrapnel wounds. The attack was the latest challenge to Maliki's crackdown in Baghdad, seen as a final attempt to halt all-out civil war. Aides to the vice president, a member of the Shi'ite majority that dominates the U.S.-backed government, said he was later discharged from a U.S. military hospital in the Green Zone, a government compound that also houses the U.S. embassy. Police said he was still in hospital. "He has light shrapnel wounds in different parts of his body but it is not serious," a political source from the ruling Shi'ite Alliance said, referring to the vice president. Abdul-Mahdi is one of Iraq's two vice presidents. The other is Tareq al-Hashemi, a Sunni Arab. The cause of the blast was under investigation. Militants are increasingly using suicide vests to launch attacks because of tighter checks on roads aimed at reducing car bombs. One witness told Reuters the force of the blast had thrown Abdul-Mahdi against a wall at the ministry, in the Sunni Arab neighbourhood of Mansour in western Baghdad. "All his guards threw themselves on top of him," he said. Ghareeb's deputy had also been taken to hospital. Several senior ministry officials were among those killed, police said. The bomb wounded 31 people. Iraq's leaders are often targeted by militants engaged in Shi'ite-Sunni sectarian fighting. Around 100,000 U.S. and Iraqi troops have been deployed in Baghdad, the epicentre of Iraq's violence, to carry out the nearly two-week old security plan. But violence has continued every day, piling pressure on Maliki to crack down on both Sunni Arab insurgents and Shi'ite militias. BILLIONS OF DOLLARS Iraq's vast oil reserves are concentrated in the Kurdish north and the Shi'ite south, so sharing its oil revenues is one of the country's most sensitive issues. Sunni Arabs, dominant under Saddam Hussein but now the backbone of the insurgency, fear a bad deal will seal their political doom in oil-deprived central and western Iraq. The draft, which now goes for a vote in parliament seen as a formality, could unlock billions of dollars in foreign investment Iraq badly needs to revive its shattered economy after years of wars, international sanctions and neglect. It was endorsed with the backing of the Kurds, who had been haggling over the terms of some articles. Salih, who is also head of the committee that drafted the law, said its endorsement by the cabinet marked a major political and economic breakthrough for the war-torn country. "The council of ministers in an extraordinary meeting today approved the draft of the national hydrocarbon law," Salih said in a statement he gave to Reuters. "The law is hoped to enable Iraq to achieve its potential and utilise its revenues for the benefit of all Iraqi people." The attack involving Abdul-Mahdi was carried out while Iraqi President Jalal Talabani was in Jordan undergoing medical tests after suffering extreme exhaustion and dehydration. His office said Talabani's life wais not in danger, and denied media reports that he had undergone heart surgery. (Additional reporting by Mariam Karouny in Beirut, and Claudia Parsons, Mussab Al-Khairalla, Dean Yates and Ibon Villelabeitia in Baghdad) (Writing by Ibon Villelabeitia, editing by Tim Pearce)
