Story highlights Imran Khan is a vocal critic of U.S. drone strikes in Pakistan

He was traveling from Toronto to New York when he was questioned, he says

He reiterated his stance against drones

A State Department official says Khan was "briefly detained"

A Pakistani politician critical of U.S. drone strikes said Saturday that American authorities detained and questioned him at a Canadian airport.

Imran Khan, a former cricket star, this month led a march to the border of Pakistan's tribal region to protest drone strikes, which he says end up killing more civilians than militants.

Khan said he boarded a New York-bound plane in Toronto on Friday when two U.S. immigration officials asked him to step outside. The officials made him wait for about 40 minutes before interviewing him for another 20 minutes, he said.

"I kept asking them what was this all about, and then one guy interviewed me and he was so confused, he had no idea what he was saying," Khan told CNN by phone from Seattle, another stop on his trip.

"He was talking about some fund-raising, so I asked him to come to the point, and he said, 'We're worried you might use violence against drones.' I mean, it was so ridiculous, I didn't even know how to answer it."

Khan missed his flight, but he eventually made it to New York, and later Seattle, for fund-raisers for his political party, Pakistan Tehreek-e-Insaf. He has two more fund-raisers on the schedule, in San Francisco and Los Angeles, before he returns home to Pakistan, Khan said.

The cricket legend said he suspects U.S. officials simply wanted to make him miss an anti-drone protest Khan was scheduled to lead in the United States, without realizing the protest had already been postponed because of the Muslim holiday of Eid al-Adha

A State Department official acknowledged that Khan was "briefly delayed" before boarding the next flight to the United States.

"The issue was resolved," the official said. "Mr. Khan is welcome in the United States."

Khan has been a fierce critic of U.S. policy in Pakistan and the use of drone strikes, calling them a violation of Pakistan's sovereignty and a strategy that stokes militant anger toward Washington.

In recent years, the U.S. government has sharply stepped up the use of drone attacks in Pakistan's mostly ungoverned tribal region, widely believed to be a safe haven for militant groups fueling the insurgency in Afghanistan.

American officials say the drone strikes are an effective strategy against militant groups and insist civilian casualties are rare.

Khan says people he has spoken to in the tribal region say most of the people killed are innocent civilians.

That, he said, is counterproductive to the war on terrorism.

"If you alienate them, you lose the war, because they're the ones who are going to eventually provide logistical support," he said. "From these people will be the recruits to the militants."