Bomb in Afghanistan kills four U.S. troops

KABUL, Afghanistan - A roadside bomb killed four U.S. troops patrolling in southern Afghanistan yesterday in the deadliest single attack on international forces this year. An Afghan civilian working with the Americans also died.

The troops were patrolling with Afghan forces when their vehicle struck a bomb yesterday afternoon, the U.S. military said in a statement. It did not release the attack's location, pending the notification of relatives.

The previous deadliest attack against U.S. forces this year was a January explosion in Zabul province that killed three troops.

Twenty-nine U.S. troops have died in Afghanistan this year, compared with eight in the first two months of 2008.

The United States is increasing troop levels in Afghanistan. A record 38,000 U.S. forces now operate in the country, many in Taliban strongholds in the dangerous south, and President Obama last week announced the deployment of 17,500 more to the country.

Taliban extremists have increased attacks the last three years and now hold sway in large areas of countryside.