Pakistan's foreign minister has told her U.S. counterpart the cross-border airstrike on military outposts in northwest Pakistan is not acceptable.

Hina Rabbani Khar spoke with U.S. Secretary of State Hillary Clinton Sunday morning, telling Clinton the attack Saturday that killed at least 26 Pakistani soldiers and wounded 14 others demonstrated a complete disregard for human life. Khar said the attack has sparked rage in Pakistan.

Pakistan retaliated by shutting down all NATO supply lines through its territory to Afghanistan and ordering the U.S. to vacate an airbase in southwestern Baluchistan province within 15 days.

Pakistani Prime Minister Yousuf Raza Gilani and top military and government leaders said Saturday the Pakistani government “will revisit and undertake a complete review of all programs, activities and cooperative arrangements with US/NATO/ISAF.” They called for “strong and urgent action” against those responsible for the deadly incident.

The United States says Pakistan's tribal belt is a sanctuary for the Taliban, which has been fighting for 10 years against U.S. troops in Afghanistan.

U.S. Defense Secretary Leon Panetta and Secretary of State Clinton issued an unusual joint statement Saturday expressing their “deepest condolences” for the incident in Pakistan's border region. They stressed they would press for an immediate investigation by NATO.

U.S. officials have not given a detailed account of the raid on the Pakistani outposts, nor have they confirmed that Pakistan shut down supply lines to Afghanistan.

NATO spokesman General Carsten Jacobson said Afghan and coalition forces were operating in the border area of eastern Afghanistan when “a tactical situation” prompted them to call in close air support. He said it was “likely” that coalition airstrikes caused Pakistani casualties.

In Islamabad, U.S. Ambassador Cameron Munter was summoned to the Foreign Ministry to explain the incident. Munter said he promised the U.S. would work closely with Pakistan in any investigation.