By Adam Shaw

Fox News

House Republicans warned Defense Secretary Jim Mattis on Wednesday that lawsuits filed against the Pentagon by environmental advocacy groups in the U.S. may be unwittingly helping America’s adversaries, particularly China.

A letter sent by members of the House Committee on Natural Resources warned that “while some lawsuits represent sincere and justified concerns about the effect of federal actions on the environment, others may be maliciously filed to stop, restrict, delay, or impose additional costs on U.S. military activities.”

Committee Chairman Rob Bishop, R-Utah, and Subcommittee on Oversight and Investigations Chairman Bruce Westerman, R-Ark., pointed specifically to U.S. engagement in the Asia-Pacific region, noting the military has faced lawsuits dating back decades alleging environmental violations.

They wrote that the Navy has been restricted in testing and training due to litigation, citing lawsuits led by the Natural Resources Defense Council focusing on how marine life are impacted by the Navy’s use of active sonar and underwater explosives.

“Active sonar is the most effective means of detecting the ultra-quiet diesel electric submarines deployed by foreign navies, such as China’s People’s Liberation Army Navy,” the letter noted.

The letter also cited lawsuits by Earthjustice that have hindered live-fire exercises in Hawaii and a fight by environmental groups to prevent the relocation of a Marine Corps Air Station in Okinawa, Japan to a less densely populated area.

The lawmakers claimed that for America’s adversaries, “such lawsuits may serve as an inexpensive tool or a military windfall which reduce U.S. defense capabilities.”

“Accordingly, environmental groups that bring such lawsuits may be knowingly or vulnerable to unwittingly serving as proxies for our foreign adversaries,” the letter states, before warning that such groups “could perform as self-funded, self-sufficient, and perpetual ‘launch and forget’ weapons.”

The committee requested the Pentagon provide related information and documents, including those that identify foreign entities working to use U.S.-based groups as “proxies” in litigation against the Pentagon.

The letter comes after the committee raised red flags about the NRDC’s advocacy work, suggesting it is at risk of being coerced by China -- suggesting it may even need to register as a foreign agent. The group responded in a statement by defending its “American values.”

“NRDC seeks environmental solutions that are grounded in sound science, U.S. law and the public interest,” Bob Deans, director of strategic engagement for the NRDC, said. “We work on behalf of every American to protect our people against dangerous pollution and leave our children a livable world. Those are American values, American goals, and advancing them is manifestly in our national interest, as we have consistently demonstrated for nearly 50 years.”