(NewsNation) — The head of NASA says the U.S. is entering a new space race, this time with China, raising concerns about the country’s intentions.

China successfully landed a lunar probe on the far side of the moon, planting the country’s red and gold flag. This is a significant advance for China’s space program, but for the U.S., it raises concerns about the country’s goals.

NASA Administrator Bill Nelson has been saying for some time he believes China’s secretive space program, which the country claims is civilian, is actually a military effort.

Nelson has warned for months the Chinese program’s potential goals could include the creation of anti-satellite spacecraft or missiles.

China’s spacecraft landed and unfurled the flag before the moon lander returned with rock and soil samples from the far side of the moon. That’s left concerns with U.S. officials that China could try to make some kind of territorial claim on the moon.

“My concern is that they don’t get there first and say this is our area, you stay out,” Nelson said. “Because the south pole of the moon, we think, because we think there is water there. And if there’s water, there’s rocket fuel. That’s one reason we’re going to the south pole of the moon.”

China’s moon mission also may be a preview of the country’s desire to put humans on the moon by the end of the decade.

The U.S. is also trying to return humans to the moon through the Artemis program in the next few years, coming decades after the last manned trip to the moon in the 1970s.

Artemis Two is expected to launch no sooner than September 2025, a date that has been pushed back from earlier plans. That mission would send four astronauts to the moon.

The plans are part of efforts to establish a long-term presence on the moon for science and research and, hopefully, create a launching point for crewed missions to deeper space.