NATO and Afghan forces have launched an offensive against militants to regain control of a remote district in southern Afghanistan.

NATO's International Security Assistance Force (ISAF) says troops began an operation Wednesday in Ghazni province, after militants took over the Ajiristan district on Monday.  ISAF says some militants in the area were killed during a coordinated airstrike.

Meanwhile, a district police chief was killed when a roadside bomb struck his convoy in Nangarhar province.

In Wardak province, the U.S.-led coalition says troops killed militants during a search in the Saydabad district Tuesday.

In Washington, a Defense Department spokesman said the decision to send more U.S. troops to Afghanistan will be left to the next presidential administration.

U.S. commanders have been asking for three more combat brigades, or about 10,000 troops, to help confront rising violence in Afghanistan.

On Tuesday, the top U.S. military officer, Admiral Mike Mullen, said the U.S. does not have the man-power to send urgently needed military reinforcements to Afghanistan.  He said U.S. troops are all heavily committed in Iraq.

In other news, the U.S.-led coalition said U.S. and Afghan forces killed militants Monday during clashes in the Maruf and Shah Wali Kot districts of southern Kandahar province.