"The United States is very concerned by the People's Republic of China's provocative military activity near Taiwan, which is destabilizing, risks miscalculations, and undermines regional peace and stability," US State Department spokesman Ned Price said in a statement.

"We urge Beijing to cease its military, diplomatic, and economic pressure and coercion against Taiwan."

Beijing marked its National Day on Friday with its biggest aerial show of force against Taiwan to date, buzzing the self-ruled democratic island with 38 warplanes, including nuclear-capable H-6 bombers.

That was followed by a new record incursion on Saturday by 39 planes, said Taiwan, which accused Bejing of "bullying" and "damaging regional peace."

"It's evident that the world, the international community, rejects such behaviors by China more and more," Premier Su Tseng-chang told reporters on Saturday.

Democratic Taiwan's 23 million people live under the constant threat of invasion by China, which views the island as its territory and has vowed to one day seize it, by force if necessary.

Beijing has ramped up pressure on Taipei since the 2016 election of President Tsai Ing-wen, who has said she views the island as "already independent" and not part of a "one China."

Under President Xi Jinping, Chinese warplanes are crossing into Taiwan's air defense identification zone (ADIZ) on a near daily basis.

In the last two years Beijing has begun sending large sorties into Taiwan's ADIZ to signal dissatisfaction at key moments -- and to keep Taipei's ageing fighter fleet regularly stressed.

Xi has described Taiwan becoming part of the mainland as "inevitable."

US military officials have begun to talk openly about fears that China could consider the previously unthinkable and invade.

Protection of Taiwan has become a rare bipartisan issue in Washington and a growing number of Western nations have begun joining the United States in "freedom of navigation" exercises to push back on China's claims to the South China Sea and Taiwan Strait.

Price reiterated that the United States would "continue to assist Taiwan in maintaining a sufficient self-defense capability."

"The US commitment to Taiwan is rock solid and contributes to the maintenance of peace and stability across the Taiwan Strait and within the region," he said.