Lockheed Martin won a three-year extension on an agreement to service Canadian Navy frigates, even as U.S. defense contractors brace for fallout from President Trump’s trade dispute with the country and U.S. allies that have been lucrative customers.

Under the agreement, Bethesda, Md.-based Lockheed’s Canadian subsidiary will provide support for combat management systems for 12 Halifax-class ships. The backbone of the Canadian Navy, Halifax frigates were originally designed for surface and anti-submarine warfare on the open sea, but have adapted to handle attacks from smaller, easier-to-maneuver ships closer to shore, according to the government.