BAGHDAD - At least 21 people died in a dozen blasts and a series of shootings across Iraq on Thursday, underscoring the country's uphill struggle to stamp out a stubborn insurgency. No group claimed responsibility for Thursday's bombings, but a local al-Qaeda affiliate and other radical Sunni Islamist groups have carried out at least one major assault a month since the last American troops left in December. Al Qaeda's local wing, the Islamic State of Iraq, says it has begun a new offensive, and security experts say it has benefited from some arms, cash and better morale thanks to the inflow of Islamist fighters into neighboring Syria. Security has been increased in Baghdad ahead of the end of the Muslim holy fasting month of Ramadan next week, a period when analysts believe insurgents may attempt a major attack. In the capital Baghdad, a car bomb killed six civilian and wounded 28 in the mainly Shi'ite district of Husainiya on Thursday, police and hospital sources said. Just north of the capital, in Taji, another car bomb injured nine people. Four car bombs exploded in the city of Kirkuk, 250 km (150 miles) north of Baghdad, killing two people and wounded 18, police and hospital sources said. Kirkuk, which sits on massive oil reserves, is at the heart of a dispute between Baghdad's central government and the country's autonomous Kurdistan region, both of which claim the city as part of their area of territorial control. Overnight attacks on police checkpoints in the cities of Baquba and Falluja killed six policemen and wounded 13, police and hospital sources said. There were car bombs, shootings and sticky bombs -- often explosives attached to vehicles with a magnet -- in other towns. Sunni Muslim insurgents have launched a string of attacks on Shi'ite targets to try to reignite the sectarian violence that killed tens of thousands of people in 2006-2007 and to undermine the country's Shi'ite-led government. The Islamic State of Iraq insurgents have also said their suicide bombers attacked a counter-terrorism unit in Baghdad in August to try and free prisoners held there. Iraq's security forces are generally seen as capable of containing the insurgents, but a crisis among Shi'ite, Sunni and Kurdish factions is fueling sectarian tensions and paralyzing their power-sharing government.
