Pakistan halts drone anti-protest led by ex-cricketer Imran Khan EPA / Saood Rehman Imran Khan, head of opposition political party Tehrik-e-Insaf, speaks to supporters during a protest march toward the troubled South Waziristan region in Pakistan on Sunday. Pakistani security forces blocked a convoy carrying thousands of Pakistanis and a small contingent of U.S. anti-war activists from entering a lawless tribal region along the border with Afghanistan on Sunday to protest American drone strikes. The group, led by cricket-star-turned-politician Imran Khan, was turned back just miles from the border of South Waziristan. Khan, leader of the Tehrik-e-Insaf (PTI) party, was briefly detained. He was later released and sent back toward Tank district along with the protesters. Pakistan's military and the civilian government publicly complain that the U.S. strikes - aimed at remnants of al-Qaida and the Taliban - infringe the country's sovereignty and cause civilian casualties. Yet the government has taken little concrete action against the strikes. Khan, who blames the government for allowing the U.S. to operate in the country, had planned to lead the protest from the capital into South Waziristan, a tribal area frequently hit by the drone strikes. But authorities blocked the protesters' path with shipping containers on the highway. After several delays the army told protesters it was unsafe to be on the road after dark and they turned back. "The drones are inhumane," Khan said, donning a white turban as he stood on a vehicle in the town of Tank, surrounded by thousands of protesters. Are these people not humans? These humans have names. Drone attacks are a violation of human rights," he said. Government officials and PTI leaders said a large number of security personnel were deployed on the Tank-Jandola road. The PTI workers said when their convoy led by Khan entered South Waziristan, the soldiers stopped his vehicle and took it away. Imran Khan's vehicle was leading a motorcade of peace march toward his last destination Kotkai in South Waziristan after crossing over several barricades set up by the government to stop them from proceeding towards Waziristan. The security forces took him into custody and later freed him and returned all participants of the peace march to Tank," a PTI activist, Hussain Shah, told NBC News by telephone. Senior PTI leader Shah Mahud Qureshi said the military officials told protesters that the road toward Kotkai, in South Waziristan, is dilapidated and it would be better for them to go back. "We decided to peacefully return and organize (a) rally in Tank," the party leader said. About 30 Americans traveled to Pakistan to take part in the protest and apologize for the strikes to men and women who had been maimed or lost family members. "We have to put pressure on the United States government," said Billy Kelly, a 69-year-old Vietnam veteran from New York. The United States says the strikes have killed top Taliban and al-Qaida commanders and civilian casualties are minimal. But it refuses to say how targets are selected or how the military determines whether the dead were fighters or civilians. The Bureau of Investigative Journalism, which tracks drone strikes, said between 1,232-1,366 people had been killed since the strikes began in 2004. Between 474-884 were believed to be civilians, it said. A recent report, Living Under Drones, a study by law professors at Stanford and New York Universities, said that large swathes of Pakistan's tribal areas were terrorized by the drones. Civilians were scared to go to school or work in case they were targeted, the report said. Getting accurate data on casualties and the effects of drones is extremely difficult since the government allows few foreigners into the tribal areas and the Taliban often seal off the sites of strikes. Drones also often attack people arriving at the site of the strike. The march highlighted the way that drones complicate the Pakistani government's already uneasy relationship with the United States. Americans often justify the strikes by saying Pakistan is unable or unwilling to crush the insurgency. "The government is making pro forma protests but Imran has shown the world he will do something," said Shamsad Ahmed Khan, a former foreign secretary. He noted the government declared a national day of protests over a blasphemous film last month, but it had never called for such a protest over the drone strikes. Some Pakistanis, however, questioned why the marchers were not talking about atrocities by the Taliban or the Pakistani army, both of which have killed far more people than the drone strikes. Columnist Saroop Ijaz said that the Taliban frequently and deliberately target civilians by bombing hospitals, schools, funerals and shrines. "Drone attacks began and continue because of the ideology of murder and not the other way around," he wrote in the Express Tribune. The Taliban denounced the march as political theater ahead of next year's elections and condemned Khan and his party as "secular and liberal." NBC News" Mushtaq Yusufzai and Waj Khan and Reuters and The Associated Press contributed to this story.