OTTAWA: Canadian Prime Minister Justin Trudeau on Friday condemned what he said was a lack of transparency around China's prosecution of two citizens accused of espionage and said Ottawa's top priority was their release.

"Their arbitrary detention is completely unacceptable, as is the lack of transparency around these court proceedings," he told a news conference.

The trial of Michael Spavor ended on Friday after a closed-court hearing of around two hours. The case against Michael Kovrig is due to start on Monday.