Canada's foreign minister, Maxime Bernier, has resigned after he admitted leaving classified documents in what he called "a non-secure location". His former girlfriend, Julie Couillard, told Canadian media the papers had been left at her flat in Montreal in April. Canadian Prime Minister Stephen Harper said it was a serious security breach. Mr Bernier had been under pressure to quit after it emerged that Ms Couillard had previous relationships with men connected to organised crime.