The Chinese foreign ministry said on Monday that China has lodged "stern representations" with the United States, after U.S. President Joe Biden said U.S. forces would defend Taiwan in the event of a Chinese invasion.

China reserves the right to take all necessary measures in response to activities that split the nation apart, said Mao Ning, spokesperson at the foreign ministry, at a regular media briefing.

"There is only one China in the world, Taiwan is part of China, and the government of the People's Republic of China is the only legitimate government of China," said Mao. (Reporting by Yew Lun Tian; writing by Ryan Woo)