CHASHMA, Pakistan — Hundreds of political activists, led by the opposition politician Imran Khan and accompanied by 32 American peace activists, departed Pakistan’s capital on Saturday in a convoy headed toward the country’s tribal regions to protest American drone strikes.

Mr. Khan’s political party, Pakistan Tehreek-e-Insaaf, calls the motorcade a “peace march” to demand an end to American drone strikes, which he says kill innocent civilians and breed militancy.

The convoy’s destination is Kotkai, a town in the South Waziristan tribal region, which is the hometown of Hakimullah Mehsud, the leader of the Pakistani Taliban, and is currently under the control of the Pakistani military.

Mr. Mehsud is believed to be hiding in North Waziristan, which has become a militant redoubt.

Mr. Khan had said that he planned to reach Kotkai by noon on Sunday, but by Saturday evening it appeared more likely that the convoy, which consisted of at least 200 vehicles, would not be allowed to enter South Waziristan by the Pakistani civil and military authorities, who cited security concerns.