ISLAMABAD: Pakistani politician Imran Khan has said he was pulled off a New York-bound plane by US immigration officials and interrogated about his view on American drone strikes in his country.

Khan, leader of the Pakistan Tehrik-i-Insaf (PTI), was headed to New York to attend a fund raiser organised by his party when he was stopped by US officials in Toronto on Friday, he said.

“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,” he wrote on Twitter.

Officials from Khan’s party said the delay meant he missed his flight and was late for the party fundraising event in New York, but he insisted “nothing will change my stance”.

“My stand on drones is very clear. I did not say sorry to them,” Khan said after arriving in New York, according to a local news channel.

“I still couldn’t understand why they did this. The official was questioning me about drones but I think he himself didn’t understand what he was talking about,” he added.

The US ambassador to Pakistan “knew that I will always oppose the drone attack, then why (did) they issue me visa”, he later said at the fund raising event.

Ali Zaidi, a senior party leader demanded “a prompt and thorough inquiry into this sordid episode” and sought “an unconditional apology from the US government”.

US officials in Washington declined to comment.

Khan has campaigned vociferously for an end to the controversial US campaign of missile strikes against suspected Taliban and al Qaeda militants in Pakistan’s tribal areas.

He argues they are illegal and counterproductive and earlier this month he led thousands of supporters – and a group of American peace activists – on a march to the edge of the restive tribal districts to protest against drones.

Khan led the two-day protest march against US drone strikes with some 15,000 of his supporters and dozens of Western peace activists to Tank, the last town before the semi-autonomous tribal belt.

It was an unprecedented gesture from a mainstream politician in one of the most dangerous parts of the country, a semi-autonomous zone that is a hotbed of activity by Taliban and al Qaeda militants.

Pakistani authorities did not allow the protesters to enter the tribal district of South Waziristan – where missiles fired by US drones routinely target militants – for security reasons and blocked the road to Tank with shipping containers.

US officials say the drone program is a key weapon in the war on terror. But peace campaigners condemn it as a breach of international law, Pakistanis as a violation of sovereignty that breeds extremism, and politicians including Khan as a sign of a government complicit in killing its own people.

Khan, who is campaigning ahead of general elections next year, has made opposition to the drone programme a key plank of his party’s policy.

Critics accuse him of merely trying to further his own career and of ignoring both atrocities blamed on militants and abuses by the Pakistani army.

Although leaked US cables have revealed tacit support for the drone strikes from Pakistan’s military and civilian leaders, Islamabad has increasingly condemned the programme as relations with Washington have deteriorated.