Suicide bomb hits foreign troop convoy in Kabul

KABUL (Reuters) - A suicide bomber blew himself up near a convoy of U.S. military vehicles in the Afghan capital on Tuesday, causing casualties among foreign troops and Afghan civilians, security sources and an Afghan soldier said.

The security source said the attack happened on a road leading east from the city centre, close to several large bases for foreign troops.

"It was a suicide attack on foreign troops. There are casualties among Afghan civilians and foreign forces," the source said.

U.S. and NATO-led forces issued a statement in which they said they were aware of an explosion outside the main gate of Camp Phoenix, a U.S. base. It said initial reports indicated the cause of the explosion was a car bomb.

U.S. soldiers were blocking access to the scene on the Jalalabad road, the main highway leading east out of the capital, a Reuters witness said.

An Afghan soldier at the scene told Reuters a suicide bomber had blown himself up as a U.S. military convoy drove by.

Violence in Afghanistan is at its highest levels since the war began in late 2001, with Taliban insurgents spreading attacks out of traditional strongholds in the south and east into previously peaceful areas.

Militants have carried out an increasing number of attacks inside the capital with suicide bombings and commando-style attacks aimed at both military and diplomatic targets.

On January 18, Taliban gunmen launched a brazen assault inside the centre of the city with suicide bombers blowing themselves up at several locations and militants battling security forces from inside a shopping centre engulfed in flames.

(Reporting by Hamid Shalizi; Writing by Jonathon Burch; Editing by Emma Graham-Harrison and Paul Tait)