PHNOM PENH (Reuters) - A U.S. Navy aid unit has been told to leave Cambodia, the U.S. embassy said, in a new sign of the Southeast Asian country loosening links with Washington as it strengthens ties with Beijing.

A Chinese navy ship is seen docked after an exercise with Cambodian naval officers in Preah Sihanouk province, Cambodia February 26, 2016. REUTERS/Samrang Pring

The departure of the U.S. Navy Mobile Construction Battalion - known as the Seabees - meant the cancellation of 20 planned projects, including at schools and hospitals, the embassy said on its Facebook page on Monday.

“Last week, the Royal Government of Cambodia notified the Embassy of its decision to postpone indefinitely the Seabees program,” the embassy said. “We are sad to see the Seabees go, but proud of their accomplishments over the last nine years.”

Cambodian defense ministry spokesman Chhum Socheat said he was unaware of such a decision.

Cambodia has gone further than other Southeast Asian nations in courting China and the shift away from Washington has continued under U.S. President Donald Trump, despite Cambodian Prime Minister Hun Sen’s professed admiration for him.

Relations have been strained by U.S. criticism of a legal change that made it easier for the government to ban political parties and by renewed Cambodian demands for the cancellation of $500 million in debts dating from the war era of the 1970s.

In January, Cambodia suspended joint military exercises that were due to have been held in June. Cambodia said it was because it would be too busy with elections then and rejected any connection to China.

Last year, Beijing held a joint naval drill with Cambodia for the first time. Cambodia’s armed forces have benefited from Chinese training and equipment including jeeps, rocket launchers and helicopters.

Elsewhere in Southeast Asia, Philippine President Rodrigo Duterte has boasted of his new friendship with China despite a longstanding territorial dispute. Thailand’s military junta has increased purchases of Chinese hardware, including a further 10 tanks approved by the cabinet on Tuesday.

The reduction in military links with Cambodia would be a setback for U.S. strategy in the region but Hun Sen could also end up losing out, said Carl Thayer, professor at the University of New South Wales at the Australian Defense Force Academy.

“His anti-U.S. actions will only increase Cambodia’s dependency on China,” he said.