– Russia and China are engaged in robust efforts to fight wars in space, developing technology and weapons designed to take out U.S. satellites that provide missile defense and enable soldiers to communicate and monitor adversaries, according to a pair of reports released this week.

The reports punctuate a growing concern by the Pentagon, which has been increasingly vocal about the vital role space plays in modern conflict. And they come as some members of Congress have pushed for a “space corps,” a proposal that seemed to gain the backing of President Donald Trump, who in a recent speech said that “space is a war-fighting domain, just like the land, air and sea. We may even have a space force. … We have the Air Force; we’ll have the space force.”

The proposal by the House last year to create the Space Corps, which would become the first new military service branch since the Air Force was created in 1947, was unsuccessful after top Pentagon leaders came out against the measure. But the Pentagon is increasingly concerned that its assets in space, which are vital for modern warfare, are vulnerable.

“We have lost a dramatic lead in space that we should have never let get away from us,” Rep. Mike Rogers, R-Ala., said as he was pushing the space-corps concept last year. “So that’s what gave us the sense of urgency to get after this.”

That view is shared broadly. The White House’s National Security Strategy, released late last year, cited space as one of the Pentagon’s top priorities and warned: “Any harmful interference with or an attack upon critical components of our space architecture that directly affects this vital U.S. interest will be met with a deliberate response at a time, place, manner and domain of our choosing.”

As reports released this week from the Secure World Foundation and the Center for Strategic and International Studies show, the countries have been quite active in recent years, posing a significant threat to the United States. Though much of the foreign nations’ activities in space are secret, the reports are an attempt to spotlight some of the publicly known activities to create a clearer picture of the threats the United States could face in space.

In 2007, China fired a missile that blew up a dead satellite, a worrisome demonstration of power that put the Pentagon on notice that its assets in low orbit could be vulnerable. Then, in 2013, China fired a rocket into a far more distant orbit, 22,000 miles away, where some of the nation’s most sensitive satellites live.

More recently, Russia sparked concern when one of its satellites flew between two commercial Intelsat communications satellites and then sidled up to a third.

The threats range from missiles that could destroy satellites by physically taking them out, to cyberattacks and even lasers and jammers that could disrupt sensors and blind the eyes and ears the Pentagon relies on in orbit. While the worst-case scenario of blowing up satellites concerns military officials, the “non-kinetic” attacks can be just as effective, said Brian Weeden, the director of program planning at the Secure World Foundation, “and are becoming a lot more prevalent.”

The organization’s report noted that “China has recently designated space as a military domain, and military writings state that the goal of space warfare and operations is to achieve space superiority using offensive and defensive means.”

In 2014, China hacked U.S. weather and satellite systems operated by the National Oceanic and Atmospheric Administration.

Russia has also been active in space, heightening tensions between the former Cold War adversaries.

Unlike China, Russia “is actively employing counterspace capabilities in current military conflicts,” including with Ukraine, the report said.

But the Pentagon is not sitting on its hands. In the fall, the Air Force launched its X-37B, a classified space plane built by Boeing that can stay aloft for months at a time. Though the Air Force would say only that the mission is to carry small satellites and “demonstrate greater opportunities for rapid space access and on-orbit testing of emerging space technologies,” many officials say it could also be used to gather intelligence.