An improvised bomb attack killed two U.S. service members Monday in southern Afghanistan where U.S. and NATO troops have stepped up their operations against insurgents in recent months, AP qouted NATO saying. Also in the south, a British soldier was killed in an attack on a foot patrol and another NATO service member died in a blast Sunday, NATO and British officials said Monday. Militants this year have increased their use of roadside bombs, which now account for the majority of U.S. and NATO casualties. NATO spokesman Brigadier General Eric Tremblay said two NATO service members died Monday in a bomb attack. U.S. Navy Chief Petty Officer Brian Naranjo confirmed that the two were Americans. No other details were provided. The British soldier, who has not been named, was shot while patrolling in the Babaji district of Afghanistan's southern Helmand province, Britain's defense ministry said. The soldier's death brings to 214 the number of British military personnel killed in Afghanistan since operations there began in the aftermath of the Sept. 11 attacks in 2001. Another service member from NATO's International Security Assistance Force was killed Sunday in a bomb blast in the south, NATO said Monday. No other details, including the service member's nationality, were released. Violence has risen across Afghanistan in the last three years as the resurgent militant groups regained control of large swaths of countryside. -- SPA