Blast kills 3 coalition soldiers in Afghanistan

KABUL (Reuters) - An explosion killed three U.S.-led coalition soldiers while they were on a foot patrol in southern Afghanistan on Thursday, the U.S. military said.

Violence has surged in Afghanistan this year as Taliban insurgents step up their effort to oust the pro-Western Afghan government and drive out foreign troops through a campaign of guerrilla warfare backed by suicide and roadside bomb attacks.

The U.S. military did not say exactly where in southern Afghanistan the incident took place and did not release the nationality of the soldiers, but the vast majority of coalition troops are American.

Elsewhere, a rocket landed outside the international civilian airport in the Afghan capital, Kabul, on Thursday, but there were no casualties, the NATO-led force said.

Rocket attacks in Kabul are relatively rare and cause few, if any, casualties, but are a reminder that Taliban insurgents are able to threaten security even in the heavily guarded capital.

The rocket landed in front of the civilian terminal, a spokesman for NATO's International Security Assistance Force (ISAF) said. Another rocket was also fired, but it was not clear where it landed.

Kabul airport is the main hub for international flights to and from Afghanistan as well as for internal flights. ISAF, the Afghan National Army Air Corps and the United Nations also operate separate terminals around the same airfield.

(Reporting by Jonathon Burch; Editing by David Fox)