ISLAMABAD - Supplies for NATO troops in Afghanistan from Pakistan were resumed early Monday after a two- day protest sit-in in the country's northwest against US drone strikes, contractors said.

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The Pakistani authorities had stopped NATO supply trucks and oil tankers as thousands of people had been camped on Saturday and Sunday on the main highway between Pakistan and Afghanistan.

Cricketer-turned politician, Imran Khan, party head of the Tehrik-e-Insaf (Justice Movement), who led a sit-in in the city of Peshawar announced Sunday night he would stop supplies to NATO forces if the US did not halt drone strikes in a month time.

The US uses pilotless drone aircraft to rain missiles on the Pakistani tribal regions to target Taliban and al-Qaeda militants, who the CIA says plan cross border attacks into Afghanistan.

Tribesmen and Pakistani leaders argue that mostly civilians are killed in the American strike and an attack last week killed 25 people including women and children in North Waziristan tribal region.

Anger has been at peak against a late March strike which killed over 40 tribesmen, who had gathered in Datta Khel area of North Waziristan to resolve a local dispute. Army chief General Ashfaq Pervaiz Kayani had angrily reacted to that strike and the tribesmen vowed revenge.

President of the NATO contractors association Shakir Afridi said that supplies for the foreign forces resumed early Monday and hundreds of stranded trucks and oil tankers headed to Afghanistan.

Despite the public resentment and Pakistan's official protest, the US administration has rejected possibility to halt the strikes. After the meeting of the CIA and Pakistan intelligence chiefs, a CIA spokesman said that the US will take every action to protect its citizens.

Suspected militants also target the NATO trucks and have torched hundreds over the past several years. The US has already struck an agreement with Russia for alternate supply route and is planning to sign similar deals with Central Asian states.