Pakistan's anti-drone politician and former cricket-star, Imran Khan, was taken off an international flight from Toronto to New York for questioning over his political views, and his critical stance on US foreign policy, immigration officials have confirmed.

"I was taken off from plane and interrogated by US Immigration in Canada on my views on drones. My stance is known. Drone attacks must stop," Khan tweeted yesterday after his questioning.

Ali Zaidi, an official in Khan's party demanded "a prompt and thorough inquiry into this sordid episode" and "an unconditional apology from the US government".

Khan was on his way from a public lecture in Toronto to a fundraising event in New York. He was eventually released and allowed in the US. He added: "Missed flight and sad to miss the fundraising lunch in NY but nothing will change my stance."

Khan, leader of the Pakistan Movement for Justice party (PTI), and Prime Minister candidate in next year's elections in Pakistan, has been a loud voice in the anti-drone movement in Pakistan. Khan recently lead a high-profile anti-drone march aimed at south Waziristan along with US peace activists from the group Code Pink and 15,000 others.

Khan maintains that US drone strikes in Pakistan and around the world are counterproductive because they have resulted in thousands of innocent civilian deaths, cause great hardship in the country and drive up anti-US sentiment and militant recruitment.

In an interview with BBC News last month, Khan stated that if he were elected as Prime Minister he would opt to shoot down US drones that invade Pakistan, should the US and the international community continue to ignore pleas to stop the fatal strikes in the region.