Foreign Minister Lawrence Cannon says he has had 'very positive engagement' with Russian officials, though another cabinet minister said Canada's relationship with Moscow has problems. ((Chris Wattie/Reuters))

Russia has offered assurances that expulsion of two Canadian diplomats was not directed against Canada, but was an act of retaliation against NATO, Foreign Affairs Minister Lawrence Cannon said Wednesday.

Cannon met with the Russian ambassador to Canada earlier in the day for clarification on why Isabelle François, director of NATO's information office in Moscow, and her colleague Mark Opgenorth were expelled.

"The Russian ambassador came in and specifically said that for their part, it’s not a retaliation that is directed against Canada, nor against the Canadian diplomats," Cannon said.

"It's a retaliation based on … the events that took place a couple of weeks ago with the members of the NATO alliance. So, it just happened that the two information officers are Canadian."

Two Russian envoys were expelled from NATO headquarters in Brussels last week. Russian officials said that move was in retaliation for a spy case dating back to February.

The expulsion of the two senior Canadian officials will effectively cause the information office in Russia to close. Both will likely return to NATO headquarters in Brussels.

François, formerly with Canada's Department of National Defence, has worked for NATO since 1998 and took up her post with the information office in Moscow five years ago. Opgenorth is a former member of Canada's foreign service who, before joining NATO last year, worked as a political officer based out of the Canadian embassy in Moscow.

Canadian Ambassador to Russia Ralph Lysyshyn was informed of the decision to expel the two after being summoned to the Russian Foreign Ministry in Moscow early Wednesday.

When asked how the move affects Canada's dealings with Russia, Cannon said he had "very positive engagement" with Russian officials earlier this week and would continue to do so.

On April 29, NATO revoked the accreditation of two members of Russia's mission, allegedly because they were connected to a spy scandal dating back to February.

The alliance has refused to comment on the official reason for the expulsion, saying it doesn't comment on intelligence matters.

Prime Minister Stephen Harper told reporters in Prague, where he is in free-trade talks with the European Union, that NATO had to send clear signals to Russia in relation to spying, democracy and human rights violations.

"We will take whatever actions are necessary," Harper said. "Russia has a right to retaliate, but it doesn't change the fact that these [Canadian] diplomats were not engaged in anything illegal or unethical."

Defence Minister Peter MacKay, when asked Wednesday how he would describe the state of the Canada-Russia relationship, responded tersely: "In need of improvement."

'Forced to react'

The expulsions of the Canadians were initially reported on Tuesday by the Russian state news agency Interfax.

Lysyshyn said in a written statement he was told the move was a "forced decision" in response to an "unfriendly act on NATO's part."

"We naturally were forced to react," Russian Foreign Minister Sergey Lavrov said in televised comments Wednesday, adding that Russia was simply playing by the "rules of the game."

NATO said Russia had no justification for the expulsion.

"The Russian measure is very unfortunate and counterproductive to our efforts to restore our dialogue and co-operation with Russia," NATO said in a statement.

Russia promised 'firm' response

Russia's chief NATO envoy, Dmitry Rogozin, had said there would be a "firm" response to last week's expulsions.

Lavrov also withdrew from a Russia-NATO council meeting scheduled for late May to protest the "provocative" move.

Moscow was also riled by NATO military exercises in neighbouring Georgia, which fought a five-day war last summer with Russia. Both Georgia and NATO insisted Russia was welcome to participate in the exercises, but Moscow dismissed the idea.

Russia's relations with NATO have for years been fraught with tension. The country regards the international body as a Cold War relic with intrusive ambitions to expand into former Soviet countries.

Recent tensions include Russia's displeasure with efforts by Georgia and Ukraine to gain membership in the Western alliance.