The visit started after the mainland wrapped up its annual political event－the first session of the 13th National People's Congress and the 13 National Committee of the Chinese People's Political Consultative Conference, collectively known as the two sessions.

Liu was appointed head of the State Council Taiwan Affairs Office on Wednesday, the same day Chu began his fourth trip to the Chinese mainland. Liu served as China's former permanent representative to the United Nations and has been called a "veteran diplomat".

Last week's visit took place with a backdrop of US President Donald Trump signing the Taiwan Travel Act, which encourages official visits at all levels. This further increased friction in cross-Straits relations and Sino-US relations.

President Xi Jinping vowed to defeat secessionist attempts in his speech on March 20 at the closing meeting of the 13th National People's Congress.

"Chinese people have the resolve, the confidence and the ability to defeat secessionist attempts in any form," he said.

"Any actions and tricks to split China are doomed to fail. And these separatists' actions will be met with the condemnation of the people and the punishment of history."

Premier Li Keqiang also warned on March 20 at a news conference that China will not tolerate the attempts of any external force to use Taiwan as a card to cause difficulties for cross-Straits relations.