U.S. President Donald Trump said on Tuesday he had selected a design for a $175 billion Golden Dome missile defense shield and named a Space Force general to head the ambitious program aimed at blocking threats from China and Russia.

Trump announced at a White House news conference that U.S. Space Force Gen. Michael Guetlein would be the lead program manager for an effort widely viewed as the keystone to Trump's military planning.

Golden Dome will "protect our homeland," Trump said, adding that Canada had said it wanted to be part of it. The office of Canadian Prime Minister Mark Carney was not immediately available for comment.