US President Donald Trump has ordered the creation of a "Space Force", saying it would be "separate but equal" from the Air Force, the media reported.

"We must have American dominance in space. Very importantly, I'm hereby directing the Department of Defence and Pentagon to immediately begin the process necessary to establish the Space Force as the sixth branch of the armed forces. That's a big step," he said in the White House during a meeting of his National Space Council on Monday.

"We are going to have the Air Force and we are going to have the Space Force: separate but equal, it is going to be something so important," CNN quoted the President as saying.

In addition to calling for the Space Force, Trump signed Space Policy Directive -- 3 on Monday, part of his administration's push to lead in the space space.

Space Policy Directive -- 3 is primarily focused on satellite traffic management and mitigating debris in space. The policy, executive secretary of the National Space Council Scott Pace told reporters, "seeks to address the challenges of a congested space environment".

"If we're going to expand the economy in space, we need to make sure it's done in a sustainable way," Pace said.

Trump previously floated the idea of adding a "Space Force" branch to the US military -- a concept that has received some support on Capitol Hill but drawn scepticism from the Pentagon, CNN reported.