U.S. Secretary of State Hillary Clinton said Thursday that she is pleased by Afghan President Hamid Karzai's pledge to have the country's security forces take the lead over the next few years.

Speaking to U.S. and allied troops in Afghanistan, Clinton said the United States and other contributing nations have to do "everything we can to create the capacity of the Afghan government and the Afghan people to protect themselves."

Ten civilians were killed and 13 were wounded when a suicide attacker targeted a police vehicle, a spokesman for the Afghan Interior of Ministry said Thursday.

Police spotted the bomber before he reached the vehicle, but the bomber set off his explosives.

The attack occurred around 3:30 p.m. local time, the ministry said. The explosion took place in Oruzgan Province in southern Afghanistan.

Two U.S. service members were killed in southern Afghanistan on Thursday, NATO's International Security Assistance Force confirmed.

A roadside bomb in Zabul province killed the troops, ISAF said.