President Donald Trump said the U.S. should control Greenland to build a large-scale “Golden Dome” missile defense system, claiming it would also protect Canada.

Speaking at the World Economic Forum in Davos, he argued that Canada benefits from U.S. security and should be grateful, though it is unclear if Canada will participate in the project.

The Golden Dome, unveiled in May, is estimated to cost $175 billion and would use space-based sensors and interceptors for missile defense.

Canada’s Prime Minister Mark Carney emphasized that middle powers like Canada must protect their sovereignty and support Greenland and Denmark’s right to determine the island’s future, Fox News has reported.

The U.S. administration has invited Canada to join the project if they choose to contribute financially.