US and Afghan forces have captured seven suspected militants following a weekend attack in southern Afghanistan in which one American soldier was killed, the US military said Monday. The men were suspected of being involved in Sunday's attack by up to 20 insurgents on a joint US-Afghan military patrol in Helmand province in a clash that also left one militant dead. "Seven suspected enemy combatants have been captured in southern Afghanistan as Afghan and US forces continue to search for the people responsible for an attack by 15 to 20 individuals yesterday," the military said in a statement.Another American soldier and a coalition interpreter, as well as two enemy fighters, were wounded in the gunfight in the Ghrishk district of Helmand, some 520 kilometres (325 miles) southwest of Kabul on Sunday. The deaths bring the number of US troops killed by hostile fire in and around Afghanistan to 37 since the beginning of the year compared to 23 in 2004, according to the defense department statistics. This includes 16 killed when Taliban rebels shot down a Chinook helicopter in the eastern province of Kunar, the department's website said. Another 22 US troops have died in accidents or from other causes this year.