China's military said on Friday it recently held joint combat readiness exercises, patrols and combat drills in the sea and airspace around Taiwan, as a senior US senator visited Taipei for a meeting with President Tsai Ing-wen.
China, which claims Taiwan as its own territory, bristles at any form of official interaction between US and Taiwanese officials and routinely describes Taiwan as the most sensitive and important issue in its relations with Washington.
The exercises, announced by the Eastern Theatre Command of the People's Liberation Army, were organised in response to "collusion and provocations" by the United States and Taiwan, Chinese Defence Ministry spokesman Wu Qian said in a statement.
Several Chinese fighter jets crossed the median line of the Taiwan Strait on Friday in the northern part of the waterway, a Taiwan source briefed on the matter told Reuters, adding the aircraft did not enter Taiwan's airspace.
The source said it was rare for Chinese aircraft to cross the unofficial buffer, especially from Taiwan's northwest.
The aircraft "flew straight across" the median line and then "circled around" carrying out tactical operations, the person said, adding Taiwan scrambled fighter jets to intercept the Chinese planes.
"It was a clear message of provocation," the person said, citing Friday's visit to Taipei by US Senator Rick Scott, a senior Republican who chairs the National Republican Senatorial Committee and sits on the Senate's Armed Services Committee.
Taiwan's Air Force said it has a "full grasp" of the situation in the area and is "actively" defending national security. It did not elaborate.
Chinese spokesman Wu said Scott's visit to Taiwan had seriously undermined Sino-US relations and escalated tensions in the Taiwan Strait.
"The Chinese People's Liberation Army is ready for war at all times, and will take all necessary measures to resolutely thwart the interference of external forces and the secessionist attempts of 'Taiwan independence', and resolutely defend national sovereignty and territorial integrity."
After meeting with President Tsai in Taipei on Friday, Scott told reporters he believes that "the world has changed" following Russian President Vladimir Putin's actions in Ukraine.
"We all have to put ourselves in a position that we can make sure we defend the freedom we all believe in," he said. "I do think it would be helpful if Taiwan participated in RIMPAC and I hope that's what happens in the future."
The Rim of the Pacific exercise, known as RIMPAC, is billed as the world's largest international maritime exercise, with the latest one kicking off late last month with 26 nations participating in drills around Hawaii and southern California.
Taiwan's government has denounced China's stepped up military and political pressure to try and force the island to accept Chinese sovereignty, saying only its 23 million people can decide their future.
"Taiwan will continue to work closely with the United States to jointly safeguard the stability and prosperity of the Indo-Pacific region," Tsai told Scott.
US-China tensions are high over a number of issues including Taiwan, the South China Sea, trade tariffs and China's refusal to openly criticise Russian leader Putin over the war in Ukraine.
US Secretary of State Anthony Blinken is due to meet with Chinese foreign minister Wang Yi on Saturday at the G20 foreign ministers meeting in Bali.
