Insurgents ambushed an Iraqi army patrol north of Baghdad on Saturday, killing 15 soldiers in a well-planned attack, a day after the Pentagon announced 10 U.S. Marines were killed by a bomb west of the capital, Reuters reported. The Iraqi soldiers were travelling in a five-vehicle patrol near Baquba, 60 km (40 miles) from Baghdad, when they were hit by a roadside bomb. Immediately afterwards, gunmen opened fire in what police described as a well-planned assault. Hospital officials in Baquba said 15 soldiers were killed and that they were all from southern Iraq. The attack in Baquba, where there has been a surge in guerrilla activity over the past three weeks, followed the assault on the Marines near the former rebel city of Falluja on Thursday, the deadliest attack on U.S. troops for four months. The Marines were on a foot patrol near a factory when they were struck by a bomb made out of several artillery shells strung together, the Marine Corps said. The deaths raise to more than 2,120 the number of U.S. troops to have died in the war.