OTTAWA (AFP) -- Canadian Foreign Affairs Minister Peter MacKay called on the Belarusian government to release opposition leader Alexander Milinkevich after he was given a 15-day prison sentence on Thursday.

"Canada condemns the arrest and detention of Alexander Milinkevich simply for exercising his democratic right of peaceful assembly, and we call for his immediate release," said Mackay in a statement. "This is another example of how the Belarus regime is denying freedom and democracy in that country."

Milinkevich and three other opposition figures in the former Soviet republic were sentenced to 15 days in jail after being found guilty of attending an illegal demonstration.

Their conviction is the latest incident to mar relations between the two governments, which have been strained since President Alexander Lukashenko's controversial reelection last month in what Western monitors declared were heavily rigged polls.

Ottawa denied Prime Minister Sergei Sidorcky's jet a stopover in Canada one week ago, citing human rights and democracy concerns. The aircraft was allowed to fly over Canada en route to Cuba.

That came less than two weeks after Canadian journalist Frederick Lavoie was released after having spent 15 days in prison in Belarus for covering a political demonstration. "Canada has repeatedly called on the regime in Belarus to respect its citizens rights to peaceful protest and free speech," said MacKay. "Both the Prime Minister and I have denounced the actions of the Belarus government and, in March, the Government of Canada announced a decision to limit its official relations with Belarusian authorities."