The US military says two of its naval vessels have sailed through the Taiwan Strait in what is believed to be the first such mission since President Donald Trump's inauguration last month.

The US Indo-Pacific Command told NHK that the Arleigh Burke-class guided-missile destroyer USS Ralph Johnson and the Pathfinder-class survey ship USNS Bowditch conducted a "routine north-to-south" transit of the strait from Monday through Wednesday.

The command said ships transit via the Taiwan Strait and have done so for many years. It said all nations enjoy high-seas freedom of navigation within the corridor.

In response, the Chinese military's Eastern Theater Command issued a statement. The command is responsible for the East China Sea, including Taiwan, among other areas.

It said the US action sends the wrong signals and increases security risks. It said units in the command will firmly defend China's national sovereignty and security, as well as regional peace and stability.

State-run China Central Television has reported that units of the Eastern Theater Command conducted training exercises on Wednesday in waters around Taiwan's main island. It stressed that the forces can swiftly enter into a state of combat if ordered.

The report says the units have been on standby during the Lunar New Year period that started late last month. It also says China's air force conducted patrols.

In a phone call with Trump before his inauguration, Chinese President Xi Jinping urged him to deal cautiously with Taiwan, saying it concerns China's national sovereignty.

The Trump administration is apparently trying to keep China in check by sending vessels through the Taiwan Strait in order to stress freedom of navigation in the waters.