When Iranian-born Canadian citizen Farzad Alavi was denied entry to the U.S. on Jan. 10, he said a border officer told him the reason was his past mandatory military service in Iran — which the officer claimed effectively linked him with terrorists.

"They're telling me I'm a member of a terrorist organization. It's very, very difficult for me to digest," said Alavi.

"They told me never try to enter the States again."

At the time, Alavi had just suffered a horrific loss. Two days before, his wife, Neda Sadighi, was killed when Iran's military "unintentionally" shot down a Ukrainian plane after it took off from Tehran.

A grieving Alavi was travelling to the U.S. from Toronto with his son Amirali who needed a special passport stamp from the Iranian consular offices in Washington, before he could attend his mother's memorial service in Iran. There is no Iranian consulate in Canada.

"We were already devastated," said 27-year-old Amirali about his mother's sudden death. "Then the [border] incident happened. It kind of broke us down."

Farzad Alavi's wife, Neda Sadighi, was on her way back to Toronto after visiting family in Iran when she was killed in the Ukrainian plane crash on Jan. 8. (submitted by Amirali Alavi)

The plane crash occurred shortly after the U.S. assassination of Iran's top general Qassem Soleimani on Jan. 3, which heightened tensions between the two countries.

As a result, the U.S. stepped up border security, putting Iranian-born travellers under the spotlight. Alavi is one of half-a-dozen Iranian-born Canadian citizens CBC News has interviewed who were denied entry to the U.S. following the assassination.

Alavi, 55, said he and his son were held for about four hours at the U.S. border in Niagara Falls where they were fingerprinted, had their mobile phones searched, and questioned about political views and military service.

Military service is mandatory in Iran for adult men. Alavi said he stressed to border officers that he had no choice when — three decades ago — he was conscripted into the Islamic Revolutionary Guard Corps (IRGC) for his two-year service.

"I explained that this was not something that I had any power, any control over."

The IRGC is separate from Iran's mainstream military and includes the elite Quds Force, which was headed by Soleimani. U.S President Trump designated the IRGC a "foreign terrorist organization" in 2019.

Alavi, who was an orthopedic surgeon in Iran, said his obligatory IRGC service was spent working as a doctor serving patients.

"I'm not a terrorist. The whole of my life, I've saved people's lives."

Still, Alavi said these factors made no difference when he was denied entry to the U.S., apparently because of this military service.

'Indiscriminate screening policies'

Alavi and his family left Iran in 2010 for a safer life in Toronto, he said. Both he and his son became Canadian citizens in 2014.

U.S. Customs and Border Protection (CBP) confirmed Alavi was denied entry, but declined to discuss why. It did say that his "in-depth inspection" took about 1.5 hours, which is average.

"CBP takes an admissibility decision seriously," said spokesperson Aaron Bowker in an email. "The burden of proof regarding admissibility is on the traveller."

Along with cases of being denied entry, half-a-dozen other Iranian-born Canadian citizens told CBC News that — following Soleimani's assassination — they were held and questioned at the U.S. border, sometimes for hours, before being allowed to enter the country.

Professor Edward Alden said he believes the U.S. has cast too wide a net with its post-assassination screening measures.

"This is exactly what happened after 9/11," said Alden, a professor of U.S.-Canada Economic Relations at Western Washington University in Bellingham, Wash.

"You have these kinds of wide-ranging, pretty indiscriminate screening policies, and they do nothing to identify or keep terrorists out of the United States.

"But they cause considerable inconvenience and sometimes great harm to a lot of innocent travellers."

'I lost my support'

While Alavi was denied entry to the U.S., his son, Amirali was allowed to enter the country. Amirali left Iran before he had to serve in the military.

The two men had planned to share the 650-kilometre drive to Washington, and now Amirali had to make the journey alone — at 1 a.m., on icy roads — so he could get to the consular offices in time before their flight to Iran.

"I was worried," said Alavi near tears. "I lost my wife. If something happens to [my son], what am I going to do?"

Amirali Alavi is shown at his mother's funeral in Toronto. The funeral followed repatriation of her remains, which the family was unsure was possible at the time of the memorial service. (submitted by Amirali Alavi)

Amirali made it to Washington safely and both father and son were able to fly to the memorial service in Iran. But, as far as Alavi understands, he still can't enter the U.S.

"There's no clear reason for my dad to be a threat to homeland security in the States," said Amirali, who's a law student at the University of Toronto. "It's unreasonable what they're doing and they must be accountable."

Alavi said he plans to visit the U.S. consulate in Toronto to argue his case because, most importantly, he can't accept being labelled a member of a terrorist group.

"What they told me, what they called me, this is ... intolerable."