Pakistan's ex-cricket star-turned-politician Imran Khan, center, addresses his supporters during a peace march in Tank, Pakistan on Sunday, Oct. 7, 2012. The Pakistani military blocked a convoy carrying thousands of Pakistanis and a small contingent of U.S. anti-war activists protesting American drone strikes from entering a lawless tribal region along the border with Afghanistan. (AP Photo/I.A Mahsud) (I.A. Mahsud/AP)

The military on Sunday blocked Pakistan’s most vocal anti­war politician from leading thousands of his supporters into the nation’s insurgency-racked tribal region to call for a halt to U.S. drone strikes and promote peace with the Taliban.

Imran Khan, the cricket star turned politician who has earned broad appeal with his populist message, brought a 500-vehicle convoy to within 15 miles of the border of South Waziristan. But he was turned back after the army’s Frontier Corps said it could not ensure security for the several thousand rally-goers.

The military’s reasoning, Khan later told his supporters, was that the convoy had arrived too late in the afternoon to risk allowing people to gather after sunset. But all along it was doubtful that the army, which keeps a tight grip on domestic affairs, would allow Khan to enter the tribal region with a bevy of American antiwar activists from Washington-based Codepink.

It was remarkable that Khan, a candidate for prime minister, even got past Tank, the last major town before the border of South Waziristan. Since 2009, when the army launched major operations against the Pakistani Taliban and other factions, access to the semiautonomous tribal areas has been strictly controlled by the military.

Khan had wanted to stage his “peace march” in Kotkai, the home town of Hakimullah Mehsud, head of the Pakistani Taliban. His party estimated that as many as 100,000 would attend, but perhaps a tenth of that number arrived for the procession, forming traffic backups for miles.

Although most drone strikes now occur in North Waziristan, South Waziristan is where, in 2004, missiles from the remote-controlled aircraft hit their first target, militant leader Nek Mohammad Wazir.

The day turned out to be a disappointment for Codepink, which, like Khan, says the CIA’s eight-year drone campaign has caused considerable civilian casualties and spurred tribesmen to take up arms with the insurgents, who are battling to impose Islamic law, or sharia, on Pakistan. U.S. officials say the vast majority of those killed in drone attacks have been militants.

The 32 Americans had traveled for 13 hours Saturday from the capital, Islamabad, to reach the impoverished region about 290 miles to the west, in Khyber Pakhtunkhwa province. They rode in two white vans festooned with grisly posters of children whose families said they had been killed by drone-fired missiles.

Codepink is perhaps best known for its noisy disruptions of congressional hearings and puckish street theatrics in Washington. But the group’s members also are active in campaigns against Israeli policy in the West Bank, and they staged protests in Iraq before the U.S.-led invasion.

It counts as members former military officers and war veterans, some of whom traveled to Pakistan.

The majority-female delegation — in their early 20s to late 70s — traveled with no security guards despite announced militant threats against them and Khan, head of the Pakistan Justice Movement political party. They fell in line behind Khan’s procession as legions joyously waved party flags atop trucks.

By late Saturday, when the Codepink delegates finally reached a large farm belonging to a regional party official, they were mobbed by an admiring Pakistani media and given a hero’s welcome by hundreds of the candidate’s fans.

Anti-American sentiment runs extremely high in Pakistan, but the delegation focused on a simple message: “We are against drones” was emblazed in Urdu in green fluorescent script, outlined with glitter, on the oversize white bibs they wore.

“You hit people with these drones and you create instant enemies,” said JoAnne Lingle, a silver-haired Mennonite from Indianapolis. “It’s supposed to be increasing our national security and it’s doing the opposite.”

Her church raised money to send her to Pakistan. She persuaded the pastor to let her bring in a replica drone: “He gave a wonderful sermon on why we needed to do this as Christians,” she said.

On Sunday morning, the civilian administration in Tank granted Khan permission to transit through the town, removing steel containers that had blocked the road. But access to the tribal region remained doubtful — so much so that the Codepink delegation decided to avoid the traffic and head back toward the capital.

“We’re disappointed . . . but we certainly feel it was successful for us in reaching the Pakistani people with our message of peace,” said Medea Benjamin, a Codepink co-founder.

Had Khan entered South Waziristan, his visit would have been the first since the mid-1970s by a mainstream political leader. Then-Prime Minister Zulfiqar Ali Bhutto, founder of the ruling Pakistan People’s Party, visited to pledge that he would bring electricity and phone service to the tribal areas. Services improved, but Islamabad has generally neglected the Federally Administered Tribal Areas, where poverty and illiteracy are rampant.

Khan told Sunday’s rally that he wants to establish a relationship of “love, respect and more political freedom” for tribal people, promising economic development and jobs.