Three U.S.-led troops southwest of Kabul in Wardak province were also killed Thursday.

CNN: Pentagon: Taliban 'resilient' in Afghanistan

And in August 2011, insurgents shot down a Chinook helicopter, killing 30 American troops, mostly elite Navy SEALs, in Wardak province in central Afghanistan.

NPR: 5 US Troops Die In Helicopter Crash In Afghanistan

Karzai ordered U.S. special operations forces to leave Wardak province, just outside the Afghan capital, because of allegations that Afghans working with the U.S. commandos were involved in abusive behavior.

NPR: Insider Attack Kills 2 US Troops, 2 Afghans

Four girls' schools were badly damaged by fire last month in the central province of Wardak.

ECONOMIST: Even the burqa remains

It followed the U.S.'s abrupt cancellation of its planned handover of the main U.S. detention facility at Bagram Air Field, and Mr. Karzai's demand that U.S. Special Operations forces leave the strategic province of Wardak near Kabul.

WSJ: Karzai Inflames U.S. Tensions

According to an article published in November 2002 in the British The Guardian newspaper, authorities there have been investigating a series of attacks by suspected Taleban sympathisers against girls' schools in the province of Wardak, near Kabul.

BBC: Last Updated: Wednesday December 07 2005 17:49 GMT

Wardak is a critical province.

BBC: Nato announces Afghanistan Wardak agreement