(Reuters) - U.S. Senator Lisa Murkowski, a leading voice on energy policy reform in Washington, on Thursday said she is "worried" about a Chinese company's stake in MP Materials Inc, which owns the only U.S. rare earths mine and last month received a Pentagon grant.

"It kind of disturbs me to know that there's a Chinese interest there" in MP Materials, Murkowski said at a U.S. Senate Energy and Natural Resources committee hearing.

Shenghe Resources Holding Co holds about 7.7% of MP's stock, which Murkowski said "is something that we're worried about."

Las Vegas-based MP declined to comment.

(This story corrects to remove word "big" in quote in second paragraph)

(Reporting by Ernest Scheyder; Editing by Mark Porter)