At least four bombs exploded in Baghdad on Tuesday (September 26) killing at least seven people and wounding more than 40. In one incident, a suicide motorcycle bomb exploded in central Baghdad, killing three people, including a traffic policeman and wounding 10 others, police said. They said that the blast targeted police vehicles at Andalus Square . "Suddenly we heard a loud blast. All the people working in the restaurant, Al-Andalus Restaurant, were hurt," said one eyewitness. Two other civilians were killed and 12 people wounded, including eight policemen in a blast in Al-Rubaei Street in eastern Baghdad, police said. They said that a car bomb parked on the side of the road exploded as police patrols were driving in the area and when policemen and the American forces arrived at the site a roadside bomb exploded. Bombers also struck in Kirkuk, Baquba and Latifiya, and mortars fell on houses in Mahmudiya, south of Baghdad, where police also found 12 bound and tortured corpses. Saboteurs struck a gas pipeline on the road between Baiji and Kirkuk, north of Baghdad, police said. The Baiji refinery is Iraq's largest and newest refinery, built in the 1980s. It is supplied mainly from the northern oil fields around Kirkuk. The pipelines of Iraq, which hold the world's second-largest oil reserves after Saudi Arabia, have been hit by periodic sabotage since the fall of Saddam Hussein's regime in 2003. The United States has focussed its security effort on the capital Baghdad, especially around the holy month of Ramadan which began this week and saw violence surge in past years. The Pentagon said it will extend the stay of some soldiers beyond their normal one-year rotation and bring in others early to keep its troop strength in Iraq above 140,000 into next year.