Top diplomats from the Group of Seven industrialized democracies are meeting Ukraine’s foreign minister in Canada as Ukraine tries to fend off relentless Russian aerial attacks that have brought rolling blackouts across the country ahead of winter.

U.S. Secretary of State Marco Rubio may face questions from allies over U.S. military operations in the Caribbean during a meeting of Group of Seven foreign ministers in Canada on Wednesday, as concerns mount over whether strikes carried out by Washington violate international law.