(Adds Maliki's comments) 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 a ceremony. While militants defied a security crackdown in Baghdad, the cabinet endorsed a draft oil law crucial to regulating how wealth from Iraq's vast reserves would be shared by its ethnic and sectarian groups, a move hailed by Prime Minister Nuri al-Maliki as a "pillar for the unity of Iraqis". Settling potentially explosive disputes over the world's third largest oil reserves has been a top demand of Washington to maintain its support for Maliki, a Shi'ite Islamist who leads a unity government of Shi'ites, ethnic Kurds and Sunni Arabs. Police said Public Works Minister Riad Ghareeb, a Shi'ite, was seriously wounded when the bomb exploded in a meeting hall. Aides to Vice President Adel Abdul-Mahdi said he escaped with light shrapnel wounds. One police source said the death toll could be as high as 12. The bomb wounded 31 people. Maliki, under pressure to quell violence threatening to plunge the country into all-out civil war, vowed to hunt down those responsible for the attack. Iraqi leaders are often targeted by militants on either side of the sectarian divide. The bomb attack came despite a major new U.S.-backed crackdown aimed at ridding Baghdad's lawless streets of Sunni Arab insurgents and Shi'ite militias. 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. His aides said he was later discharged from 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. Ghareeb's deputy had also been taken to hospital. Several senior ministry officials were among those killed, police said. Around 100,000 U.S. and Iraqi troops have been deployed in Baghdad, the epicentre of Iraq's violence, over the past two weeks to implement the security plan. But car bombings and suicide attacks have continued, piling pressure on Maliki. 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 oil law, which now goes for a vote in parliament, could unlock billions of dollars in foreign investment Iraq badly needs to revive its shattered economy. It was endorsed with the backing of the Kurds, who had been haggling over the terms of some articles. Deputy Prime Minister Barham Salih, head of the committee that drafted the law, told Reuters that Iraq's leaders had pledged to have the law enacted by the end of May after it is approved by parliament. Speaking later to reporters, Maliki said: "The benefits of this wealth will form a firm pillar for the unity of Iraqis and consolidate their social structure." The attack on the vice president came when President Jalal Talabani was in Jordan undergoing medical tests after suffering extreme exhaustion and dehydration. His office said Talabani's life was not in danger, and denied media reports that he had undergone heart surgery. (Additional reporting by Mariam Karouny in Beirut, Claudia Parsons, Mussab Al-Khairalla and Dean Yates in Baghdad)
