Thousands of demonstrators protesting U.S. drone strikes have blocked a road in northwest Pakistan used to truck NATO troop supplies and equipment in and out of Afghanistan.

Saturday's protest in Khyber Pakhtunkhwa province is led by Pakistani politician and cricket star Imran Khan. The road leads to Torkham, one of two border crossings used to ship supplies from Pakistan to Afghanistan.

Tahir Khan, a government official at Torkham, says there is normally little NATO supply traffic on the route on Saturdays. Most trucks arrive at the border by Friday evening to clear customs.

Khan, whose party runs the Khyber Pakhtunkhwa government, has been a vocal critic of drone strikes, saying they violate Pakistan's sovereignty.

But the Pakistani government is known to have cooperated with some strikes in the past.