After US congressmen visited Taiwan, the Chinese armed forces prepared to conduct military exercises near the island, the Eastern Theater Command of the People's Liberation Army of China said. 

The CNA, Taiwan's news agency, reported that a delegation of six US congressmen, headed by Senate Foreign Relations Committee Chairman Bob Menendez, arrived on Thursday on an unannounced visit for talks with Taiwanese President Tsai Ing-wen and National Defense Minister Chiu Kuo-cheng.

However, Beijing firmly opposed any official contact between the US and Taiwan. 

"On April 15, the Chinese People's Liberation Army's Eastern Theater Command sent warships, bombers, fighter jets, and other forces to organize multi-purpose combat patrols and conduct sea and air exercises in the East China Sea and around the island of Taiwan," the command said in a statement.

According to the statement, these actions were organized in response to "recent erroneous US signals regarding the Taiwan issue," and are absolutely useless and very dangerous.

"The one who plays with fire is sure to burn themselves," the statement added.

Earlier, following media reports that US House of Representatives Speaker Nancy Pelosi would visit Taiwan, China warned that it would take strong measures if Pelosi visited, saying such a visit would have a negative impact on Chinese-US relations.

China’s Foreign Minister Wang Yi warned that “Beijing will interpret US House Speaker Nancy Pelosi’s hypothetical visit to Taiwan as a step over the red line,” according to the South China Morning Post.

"If Pelosi, a political leader of the United States, knowingly visits Taiwan, it would be a malicious provocation against China’s sovereignty and gross interference in China’s internal affairs, and would send an extremely dangerous political signal to the outside world," he said.