Chinese military forces are holding exercises near Taiwan in response to a visit by a US congressional delegation to the island.

The drills in the area of the Taiwan Strait are a “necessary measure to safeguard national sovereignty", China's Defence Ministry said in an announcement Tuesday (local time) that gave no details on the timing, participants and location of the exercises.

It said the “joint war preparedness patrol” by the Eastern Theater Command was prompted by the “seriously incorrect words and actions of relevant countries over the issue of Taiwan” and the actions of those advocating the self-governing island’s independence.

Foreign Ministry spokesperson Wang Wenbin said China considers the delegation's visit a “serious violation" of US commitments not to have formal relations with Taiwan, which China claims as its territory.

“China is firmly opposed to that and has made solemn representations to the US," Wang said at a daily briefing Wednesday.

“All risky and provocative actions against China’s reunification is like an ant trying to topple over a giant tree and is doomed to fail," Wang said.

The US has strong but informal relations with Taiwan, and tensions have been rising between the US and China over several issues including Hong Kong, the South China Sea, the coronavirus pandemic and trade.

Details on the US delegation that reportedly arrived in Taiwan on Tuesday were not immediately available.

READ MORE

• Why China wants to take control of Taiwan, and why New Zealand should care
• China's nuclear arsenal to sharply increase, US predicts amid fresh concern over potential Taiwan takeover
• China urges families to keep stock of daily necessities, sparking fears of war and panic buying frenzy
• Taiwan is becoming a flashpoint for China and the West – how does New Zealand respond?

A Chinese Defence Ministry statement from an unidentified spokesperson strongly condemned the visit, saying “no-one should underestimate the firm determination of the People’s Liberation Army to safeguard the Chinese people’s national sovereignty and territorial integrity”.

China regards Taiwan as its own territory to be annexed by military force if necessary. The sides split in 1949 during a civil war and, following a brief period of rapprochement, relations have grown increasingly tense under Taiwan's independence-leaning President Tsai Ing-wen.

During China’s National Day weekend in early October, China dispatched 149 military aircraft southwest of Taiwan in strike group formations, causing Taiwan to scramble aircraft and activate its air defence missile systems. Taiwan's Defence Ministry said this week such tactics were aimed at wearing down the island's defences and degrading morale.

In Washington, Pentagon spokesperson John Kirby said congressional visits to Taiwan “are relatively common and in keeping with US obligations under the Taiwan Relations Act", which requires the US government to ensure Taiwan has the ability to defend itself and regard threats to the island as matters of “grave concern".

The delegation arrived in Taipei on Tuesday evening aboard a C-40 Clipper jet, which departed soon afterward, according to Taiwan's official Central News Agency. Kirby said travelling on a US military jet was customary for such delegations.

Taiwanese Foreign Ministry spokesperson Joanne Ou said the ministry had worked with the American Institute in Taiwan, which is the de facto US embassy, on arrangements for the visit but gave no details. She said further information would be released at the “appropriate time”.

Although the US switched diplomatic ties from Taipei to Beijing in 1979, it retains strong informal political and military relations with Taiwan. As a vibrant democracy, Taiwan also enjoys strong bipartisan support in Congress and the US government has been boosting relations through high-level visits and military sales.