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.
Foreigners are also restricted from entering the tribal areas, and it remained unclear whether the 32 American members of the antiwar group Codepink would be allowed to go beyond Dera Ismail Khan, a city near the tribal region, where rally participants planned to spend the night.
The Taliban have threatened the convoy's participants and Mr. Khan, denouncing him as a secular politician and questioning his intentions. On Saturday, pamphlets were distributed in Tank, a town along the route, warning of possible suicide attacks and raids to kidnap the foreigners.
Mr. Khan, his supporters and the American activists appeared to be undeterred by the threats. "The group is determined to go ahead," said Alli McCracken, a Codepink spokeswoman.
"We have curtains drawn," she said. "We are low key."
Mr. Khan, a vocal critic of military operations in the tribal areas and the use of drones, said he wanted to work for peace in Pakistan, especially in the tribal areas, which have been ravaged by years of war and militancy. "The collateral damage is the killing of innocent women and children," he said before leaving Islamabad, the capital. "The war on terror has become a war of terror."
He blamed the government for trying to discourage and undermine the rally.
Along the route, supporters dotted the roadside, holding the red-and-green flags of Mr. Khan's political party, as the convoy moved through the rugged countryside of Punjab Province and into northwestern Khyber Pakhtunkhwa Province.
"We are hearing reports that the government is making it difficult for us to go to South Waziristan," said Shafqat Mehmood, a party official. "We will only know when we reach Dera Ismail Khan."
If the convoy is not allowed to enter South Waziristan, Mr. Mehmood said, "We will hold a meeting wherever."
This article originally appeared in The New York Times.