OTTAWA – Russia is using a post-Cold War agreement to conduct an aerial surveillance mission over Canadian military facilities this week, even as relations between the two countries remain frosty.

The five-day mission started Tuesday and involves an unarmed Russian aircraft flying to different parts of the country to take photos of Canadian Forces bases and other military installations.

It is being conducted through the Treaty on Open Skies, which Canada, Russia and 32 other countries signed in 1992 to encourage trust and openness about each country’s military capabilities and activities.

National Defence spokesman Evan Koronewski said the Canadian military will escort the Russians across the country to ensure they don’t stray beyond what is allowed in the treaty.

The mission comes after Prime Minister Justin Trudeau called Russia out for supporting the Syrian government, and as Canada prepares to lead a NATO force in Latvia to check against Russian aggression.

Canada conducted its own monitoring mission over Russia in November.