President Trump told a military crowd near San Diego on Tuesday that he believes the U.S. may need to create a new military branch for outer space, providing a boost to an idea that has so far struggled to gain momentum in Congress as well as the Pentagon.

"My new national strategy for space recognizes that space is a war-fighting domain, just like the land, air, and sea. We may even have a space force, develop another one: Space Force." Trump said in a speech at the Miramar Marine Corps Air Station.

"We have the Air Force; we'll have the Space Force. We have the Army, the Navy," he continued. "You know, I was saying it the other day, because we're doing a tremendous amount of work in space, I said maybe we need a new force, we'll call it the 'Space Force.' And I was not really serious, and then I said, 'What a great idea maybe, we'll have to do that, that could happen.'"

The idea of a Space Corps has been proposed in Congress as Reps. Mike Rogers, R-Ala., and Jim Cooper, D-Tenn., unsuccessfully sought to create a new military space service last year in the National Defense Authorization Act. The proposal passed the House, but did not pass the Senate and was stripped from the final bill amid opposition from the Pentagon.

Defense Secretary Jim Mattis opposed the creation of a space service last year as Congress debated the idea and the Air Force has been staunchly opposed to the new service, saying it would create unneeded bureaucracy.

But Trump's endorsement of a Space Corps could be a big boost for Rogers and Cooper, who have resurrected the idea this year and say they have the support of Deputy Defense Secretary Pat Shanahan. Rogers said he still believes the new military service will be created within the Department of the Air Force within 3-5 years.

The two House Armed Services members argue that the Air Force is botching the handling of the newest domain of warfare and allowing adversaries such as Russia and China to threaten U.S. capabilities, such as the global positioning system of satellites that much of the civilian world also relies upon. Shanahan is set to turn over a report to Congress by the end of the year detailing how the Space Corps could be created.

During his speech Tuesday, Trump mocked journalists, who he said would rush to report his suggestion of a new military branch. "That could be the big breaking story. Look at all those people back there, look at them. Oh, that fake news. Ugh," he said.

However, a few moments later, he returned to the idea. "So, think of that, Space Force, because we're spending a lot, and we have a lot of private money coming in," he said.

In December, Trump signed a policy directive establishing a goal of returning American astronauts to the moon for the first time since 1972, with longer-term goals of sending humans to Mars.