WASHINGTON (AP) — The Commerce Department has started an investigation into the impact of uranium imports on U.S. national security, a move that could result in tariffs and add another front to the Trump administration's trade fight.

Commerce Secretary Wilbur Ross says the United States produces just 5 percent of the uranium needed for the U.S. military and for electricity generation, down from nearly half in 1987.

Two U.S. uranium mining companies, UR-Energy and Energy Fuels, requested the investigation in January.

Wyoming's two US Senators praised the move. Senator Mike Enzi said, “A robust domestic uranium mining industry is not only critical for national security, it’s essential for Wyoming’s economy,” Enzi said. “Wyoming is the largest producer of uranium and it’s important our trade policies promote a global level playing field and discourage market manipulation by foreign adversaries. This appears to be a prime example of foreign countries threatening our national security through unfair trade practices.”

Senator John Barrasso said, “I applaud Secretary Ross for taking this important step for years, Russia, Kazakhstan, and Uzbekistan have undermined America’s uranium producers, including those in my home state of Wyoming. We shouldn’t rely on foreign regimes to supply America with uranium. Ensuring our nation’s uranium producers can compete on a level playing field is critical to our national and energy security.”

The probe follows an earlier national security investigation into steel and aluminum imports, which resulted in steep 25 percent duties on imports of the two metals from the European Union, Canada, Mexico, China and Japan. A second investigation focused on the threat to security posed by auto imports is ongoing.