The United States is concerned and watching closely whether China will make a move to control a seaport in Africa that services the hub of American military operations on the continent, the general in charge of U.S. forces in Africa said on Tuesday.

Gen. Thomas Waldhauser, head of U.S. Africa Command, told the House Armed Services Committee that the Djiboutian government is deeply in debt to China. Djibouti seized the port of Doraleh last week as part of a dispute with a company in the United Arab Emirates.

The port provides access to Camp Lemonnier, where four major U.S. military commands operate and the bulk of the 6,500 U.S. troops in Africa are based. Some press reports claimed Djibouti was angling to turn over control to China, which opened its first overseas military base last year in the country.

“If the Chinese took over that port, the consequences could be significant if there were some restrictions on our ability to use that, because obviously the supplies that come in not only take care of Camp Lemonnier and other places inside the continent, it is a huge activity there,” Waldhauser said. “Moreover, our U.S. Navy ships come in and out of there to refuel and whatnot. There could be some consequences, that is why it is important to watch this.”

So far, the Djibouti government has assured U.S. diplomats that there is no intention to turn over control to China, which has been busy with construction projects in the country including roads, a shopping mall and a soccer stadium, Waldhauser said.

“The Djiboutian government is probably $1.2 billion in debt to the Chinese. At some point in time that money needs to be collected,” he said.

The port dispute between the Djibouti government and the UAE company is now before a London court, where it could be settled.

China and Russia have been working to expand their influence in Africa, where the U.S. military works with partner nations such as Djibouti, Somalia and Kenya to fight terrorist and extremist groups.

The new Chinese military base in Djibouti is located “just outside our gate,” Waldhauser said, and it also deployed a hospital ship to the port to treat locals, a common practice by the U.S. when it works to build stronger ties with allies.

“The Chinese aren’t there for purely charitable reasons, we all would recognize that. They obviously believe it’s a strategic location,” said Rep. Bradley Byrne, R-Ala., a member of the House Armed Services Committee.