BRUSSELS (Reuters) - Canadian and Russian diplomats in Brussels have traded online jibes after the Canadian mission to NATO posted a tongue-in-cheek guide for Russian soldiers unclear about the Russia-Ukraine border.

The Canadians' post on Twitter featured a map of the region, with Russia labeled and colored red and Ukraine, including Russian-annexed Crimea, in blue with the tag "Not Russia".

"Geography can be tough. Here's a guide for Russian soldiers who keep getting lost and 'accidentally' entering Ukraine," the Canadian mission to NATO.

The post, prompted by Ukraine's accusation that Russian troops had crossed its border and retweeted many times, won online backing from Canada's foreign ministry.

However, Russian diplomats responded with a map of their own showing the Black Sea region and the annexed Crimea region clearly labeled as Russia.

"Helping our Canadian colleagues to catch up with contemporary geography of Europe," said the Russian team.

Russia, which is not a member of the North Atlantic Treaty Organization (NATO), has a delegation to the military alliance, but NATO has limited Russian diplomats' access to its headquarters in Brussels since April following Russia's annexation of Crimea.

(Reporting By Philip Blenkinsop; Editing by Angus MacSwan)