Thousands of people protesting U.S. drone strikes on Saturday blocked a road in northwestern Pakistan that is used to move NATO troop supplies and equipment in and out of Afghanistan — the latest sign of rising tension brought on by the strikes. The U.S.'s use of drones is deeply unpopular in Pakistan and is condemned by Islamabad as a counterproductive strategy and a violation of sovereignty, although previous governments gave their tacit support to the strikes.

The protest, led by Pakistani politician and former cricket star Imran Khan, had more symbolic value than practical impact because there is normally little NATO supply traffic on the road on Saturdays. The blocked route in Khyber Pakhtunkhwa province leads to one of two border crossings used to send supplies overland from Pakistan to neighboring Afghanistan.

Khan, whose Tehreek-e-Insaf party runs the Khyber Pakhtunkhwa government, called on federal officials to take a firmer stance to force the U.S. to end drone attacks and block NATO supplies across the country.

"We will put pressure on America, and our protest will continue if drone attacks are not stopped," Khan told the protesters.

The demonstrators dispersed after his speech, but his party put out a statement saying its supporters will begin stopping trucks carrying NATO supplies through Khyber Pakhtunkhwa indefinitely beginning Sunday night, in a move that could spark a clash with the federal government. The U.S. Embassy in Islamabad declined to comment. The U.S. leads the coalition of NATO troops battling the Taliban in Afghanistan.