U.S. forces in Africa are keeping a watchful eye on China, worried Beijing is getting closer to establishing a network of military and naval bases across the continent.

"We know the Chinese desire a network of bases around the globe," the head of U.S. Africa Command, General Stephen Townsend, told lawmakers Thursday, adding, "My concern is the greatest along the Atlantic coast of Africa."

China established its first military base in on Africa's east coast, in Doraleh, Djibouti, in 2017, raising concern among U.S. military officials who described the Chinese facility as being "right outside our gates" of the U.S. base at Camp Lemonnier.

Townsend said that since then, Beijing has worked on expanding its footprint in Djibouti as it eyes additional locations.

"What they have done in the last two years is completed a very large and capable naval pier that adjoins their base," Townsend said of Chinese expansion at Doraleh. "This pier has a capability to dock their largest ships, to include the Chinese aircraft carrier as well as nuclear submarines."

Now U.S. officials say China is looking to set up a presence farther south along the eastern Africa coast, in Tanzania, and has an even more ambitious plan for Africa's Atlantic coastline.

"This is the most significant threat from China," Townsend told members of the Senate Armed Service Committee, saying Beijing wants "something more than a place where they can make port calls and get gas and groceries."

"I'm talking about a port where they can rearm with munitions and repair naval vessels," he said. "They're working aggressively to get that."

Townsend's testimony followed similar warnings about Chinese military ambitions from other defense officials.

In March, the commander of U.S. Southern Command, Admiral Craig Faller, warned of China's attempt to reach farther into Central and South America.

"I look at this hemisphere as the front line of competition," Faller said.

Other U.S. military and intelligence officials have warned of China's efforts to supplant the United States on the world stage.

U.S. officials note Beijing has been investing heavily in Africa, pledging $60 billion in infrastructure and development funding over the past 10 years, while also expanding the number of embassies on the continent to 52, three more than the U.S. has.

There are also growing concerns about Chinese arms sales.

Despite those efforts, however, Africa Command's Townsend said the U.S. is in a position to maintain its influence and relationships.

"We don't have to compete with China head-to-head, dollar for dollar," he said. "We can target where our investments are best made."