At least two Iraqis were killed and nine injured when a bomb exploded as a group of people were queuing for work in the centre of Baghdad Tuesday, reported Deutsche Presse-Agentur dpa. In the north of the Iraqi capital, eight people were injured - some critically - when a petrol tanker exploded near a filling station. Elsewhere British soldiers in Amara, 390 kilometres south of Baghdad, clashed with gunmen Tuesday, witnesses and security sources said. British military sources in Iraq said that the soldiers, accompanied by tanks and helicopter air-cover, were conducting raids in the Hussein district of Amara and had arrested eight people. The sources added that armed clashes broke out between the UK forces and Iraqi gunmen following the arrests, injuring a number of civilians. In a separate incident in the same city, insurgents were reported to have attacked a British army patrol vehicle as it was heading towards the UK military base in the south of Amara. It was unknown whether there were any casualties. The US military overnight Tuesday arrested 11 Iraqis, including two high-ranking officers and seven soldiers, at an Iraqi army barracks in Balad, 60 kilometres north of the capital, Iraqi military sources said. The circumstances surrounding the arrests were as yet unclear. An Iraqi soldier had reportedly given information about the men in the barracks to a US military patrol. US military sources in Iraq said that there has been "no confirmation" of this incident. Elsewhere in the country, gunmen shot dead a high ranking officer entrusted with safeguarding Iraq's petroleum installations in the key Iraqi oil port of Basra, security sources said Tuesday. The sources told Deutsche Presse-Agentur dpa that unidentified gunmen opened fire on Colonel Fadel Abbas, a chief officer in charge of petroleum installation security, in northern Basra late Monday. The assailants were being sought. The killing was the latest of a string of assassinations and an escalation of violent acts in Basra. In a separate incident gunmen kidnapped the legal advisor to the president of the Bureau of Sunni Endowments in Iraq from his home in central Baghdad on Monday night, bureau sources said Tuesday. The sources told dpa that Howash Khalaf Mete'b, legal advisor to bureau president Ahmad Abdel Ghafour, was kidnapped by gunmen dressed in Iraqi security force uniforms from his home in the central Baghdad district of al-Karada.