Bomb Kills 4 U.S. Troops and an Afghan Civilian in the Country's South

KABUL, Feb. 24 -- A roadside bomb killed four U.S. troops patrolling in southern Afghanistan on Tuesday 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 Tuesday afternoon, the U.S. military said in a statement. The military did not release the attack's location pending the notification of relatives.

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

Twenty-nine American troops have died in Afghanistan this year, whereas eight U.S. service members were killed in the country in first two months of 2008.

The United States is increasing troop levels in Afghanistan. A record 38,000 U.S. troops now operate in the country, many in Taliban strongholds in the dangerous south.

President Obama last week announced the deployment of 17,000 more troops to Afghanistan to help fight a strengthening insurgency. Taliban militants have increased attacks the past three years and now hold sway in large areas of the countryside.

Taliban bombs once caused relatively few casualties among soldiers in armored vehicles, but more-powerful charges now cause massive damage even to well-protected Humvees.

In an incident Monday in the southern province of Helmand, coalition and Afghan forces killed 16 militants when responding to gunfire on their convoy, the United States said in another statement. There were no other reports of casualties, the statement said.