Three US servicemen have been killed by a roadside bomb in southern Afghanistan. A Nato spokesman said the deaths occurred yesterday. He did not release any other details. The latest deaths come as the Taliban intensifies its attacks against coalition forces in the south through roadside bombs and ambushes. The number of deaths among American troops in Afghanistan this month has now risen to 22. The month of August was the deadliest for US forces since the war with the Taliban began in 2001.