Police re-captured the administrative headquarters of the eastern Ukrainian city of Donetsk and have around 68 pro-Russian protesters in custody who are being questioned over the occupation.

Canada is recalling its ambassador to Russia for consultations about the crisis in Ukraine and is freezing preparations to take part in the Group of Eight summit in Sochi, Prime Minister Stephen Harper has said.

Harper, who talked earlier in the day with President Obama, said Canada condemned Russia's intervention in Ukraine in the strongest possible terms.