01/29/2017 09:11 EST | Updated 01/30/2018 00:12 EST

U.S. travel ban against people from 7 countries causes angst for some Canadians

Canada's major airlines are giving the all-clear to dual citizens with roots in seven predominantly-Muslim countries targeted by an American travel ban, but the country's busiest airports are still cautioning travellers to contact U.S. Customs and Border Protection before setting out.

It was initially unclear Saturday whether Canadians who are also citizens of the affected countries would be allowed to cross the U.S. border, as the State Department said that dual citizens were included in the ban.

But several hours later, Prime Minister Justin Trudeau tweeted that his government had received assurances from President Donald Trump's National Security Adviser Michael Flynn that Canadian passport holders, including dual citizens, would not be affected.

American officials have not publicly refuted that comment, and the State Department is now deferring questions to the White House and the Department of Homeland Security.

Homeland Security said in a release Sunday that it would "continue to enforce all of President Trump's Executive Orders in a manner that ensures the safety and security of the American people," but has not responded to requests to elaborate.

Representatives from WestJet and Air Canada say the airlines are allowing dual citizens carrying Canadian passports to fly to the U.S., per Flynn's comments to officials. But both the Toronto Pearson and Vancouver International airports tweeted that passengers should contact American customs before flying.

One Canadian says he's still not reassured.

Kaz Nejatian splits his time between Toronto, where his wife works as a journalist, and San Francisco, where he has an office for his tech startup, Kash. He said he's been advised not to leave the U.S. right now if he wants to return to the States any time soon.

Nejatian said he wants greater clarity than a statement from Michael Flynn to the Canadian government.

"First of all, Michael Flynn is not the director of Homeland Security, or the Secretary of State. The executive order is very specific — that only those two people get to make exceptions," said Nejatian, who was an aide to former federal immigration minister Jason Kenney.

"Second, laws have to be written down. Orders have to be written down. The Customs and Border Patrol people will follow written-down regulations. I've been advised by my immigration lawyer that despite what Michael Flynn has told the Canadian government I should not cross the border."

He said he's concerned because he was born in Iran. And despite the fact that he only holds a Canadian passport, he comes from a country with strict limits on renouncing citizenship.

On the Iranian foreign ministry's website, it says Iranians cannot renounce their citizenship without fulfilling four conditions: being 25 years old, getting permission from the Council of Ministers, relinquishing property in the country and performing military service.

Asked how long he expects to stay in the U.S., Nejatian quipped: "I don't know. I suppose, up to eight years?"

—With files from Alexander Panetta.