Washington DC - President Donald Trump's administration said Wednesday it fired a State Department employee who did not acknowledge a romantic relationship with a Chinese national.

"The State Department has officially terminated the employment of a Foreign Service officer who admitted concealing a romantic relationship with a Chinese national with known ties to the Chinese Communist Party," State Department spokesman Tommy Pigott said.

The State Department said the officer, a man whom it did not identify, said on camera that the Chinese woman "could have been a spy" but did not say if there was any proof of espionage.

The dismissed employee said his partner's father was "straight-up communist party," according to the State Department.

The Chinese Communist Party permeates life in the billion-plus country in areas from business to education, with many ordinary Chinese maintaining ties out of practicality as much as ideology.

The State Department said it was the first known dismissal taken under an executive order signed by Trump shortly after returning to office in which he ordered that all employees "faithfully implement the president's policy."

"We will maintain a zero-tolerance policy for any employee who is caught undermining our country's national security," Pigott said.

The US earlier this year said it would restrict employees in China from entering romantic relationships with locals, a rare step reminiscent of the Cold War.