The acting Pentagon chief is sharpening his argument for creating a Space Force, amid skepticism among some in Congress that it's worth the cost.

Patrick Shanahan calls the proposed Space Force a "low cost, low bureaucracy" way to stay ahead of China, Russia and other nations seeking to erase American military and technological advantages in space. He says the next big war may be won or lost in space.

Shanahan spelled out his arguments in a speech Tuesday to a space symposium in Colorado Springs. He pointedly cited China as a space threat, saying it is developing the ability to jam and target satellite communications that the U.S. military relies on in combat and in peacetime.

Congress is considering a Trump administration to establish a Space Force in 2020.