OTTAWA — The government of Prime Minister Justin Trudeau prides itself on its close ties with Ukraine. Canada has signed a free-trade agreement with Ukraine, it is providing 200 soldiers to train their Ukrainian counterparts, and it recently decided to allow sales of automatic weapons to Ukraine’s army.

So it is unlikely Trudeau was thrilled this week to hear that the interpreter who accompanied Ukrainian Prime Minister Vladimir Groysman in private talks with him in Ottawa has been arrested on suspicion of spying for Russia, Ukraine’s archenemy.

Stanislav Yezhov, a longtime aide to Groysman, was arrested by Ukraine’s Special Security Service and is expected to be charged with treason. A court ruled Friday that Yezhov will remain in custody during an investigation into the allegations.

According to the Kyiv Post, member of parliament Anton Geraschenko said he believed that Yezhov, who was detained in Kiev, Ukraine’s capital, on Wednesday, has been working for Russian intelligence services for at least two years.

Yezhov is visible in photos taken on Oct. 31 in Trudeau’s office at the Canadian Parliament when the prime minister met privately with Groysman. A Trudeau spokesman declined to comment other than to say that Yezhov was part of the Ukrainian delegation and that Canada had its own interpreter in the room, according to the Canadian Broadcasting Corp.

Canadian Prime Minister Justin Trudeau meets with Ukrainian Prime Minister Vladimir Groysman in Ottawa on Oct. 31. (Sean Kilpatrick/The Canadian Press via AP)

Daniel Livermore, a retired Canadian ambassador and onetime director-general of security and intelligence for Canada’s Foreign Ministry, said the arrest shows a “serious breach, but it’s a breach on the Ukrainian side.”

Livermore said it would be “totally irresponsible” for the Ukrainians to allow Yezhov to participate in an official delegation if they had suspicions he might be a spy.

“Assuming they knew and didn’t tell us, we ought to go back and tell them, ‘This cannot happen,’ ” he said. “We should be really pissed off.”

He said that in these situations, friendly countries do not conduct security checks on members of visiting delegations. If the Ukrainians had alerted Canadian authorities of any suspicions about the interpreter, he would not have been allowed in the room, Livermore said.

Yezhov also accompanied the Ukrainian prime minister during private talks with British Prime Minister Theresa May in July. During a visit to Poland on Thursday, May told journalists that she was aware of the reports and said the action taken against the interpreter “is a matter for Ukrainian authorities.” Yezhov also was the interpreter at a meeting last year between the Ukrainian prime minister and Vice President Joe Biden.

Yezhov, 39, once worked for the Russian-backed Ukrainian President Viktor Yanukovych, who was overthrown in 2014.

Just this week, Canadian Foreign Minister Chrystia Freeland, who, like more than 1 million Canadians, is of Ukrainian origin, was in Kiev to announce $8 million in humanitarian aid to the country. She did not comment on the arrest.

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