The United States is concerned that several African countries revoked overflight clearances for Taiwan's president at China's behest, the State Department said on Wednesday, calling the incident an abuse of the international civil aviation system.

Taiwan this week said the Seychelles, Mauritius and ​Madagascar unilaterally revoked flight permits for its presidential aircraft to cross airspace they manage on a planned trip to Eswatini, one of Taiwan's allies.

It is the first instance of a Taiwan president having to cancel an entire foreign trip due to denial of airspace access, representing a new Chinese strategy as it steps up efforts to stifle the island's efforts to engage internationally.

"These countries are acting at the behest of China by interfering in the safety and dignity of routine travel by Taiwan officials," a State Department spokesperson told Reuters, without naming the African island nations.

The US official said those countries' management responsibility of certain international airspace beyond their sovereign airspace was "solely to ensure aviation safety, not to serve as a political tool for Beijing."

"This is yet another case of Beijing waging its intimidation campaign against Taiwan and Taiwan's supporters around the world, abusing the international civil aviation system, and threatening international peace and prosperity," the official said.

Beijing should cease military, diplomatic, and economic pressure against Taiwan, the official added.

EU, BRITAIN EXPRESS CONCERN

A senior ⁠Taiwan security official had told Reuters that China applied pressure on the Seychelles, Madagascar and Mauritius, threatening economic sanctions including revoking debt relief.

China's Taiwan Affairs Office denied the claim, but expressed appreciation for the position and "practice" of the three countries in adhering to the one-China principle.

The European Union and Britain's de facto ambassador to Taiwan, Ruth Bradley-Jones, also expressed concern.

"While states exercise sovereignty over their airspace, such decisions should be taken in a transparent and predictable manner," an EU spokesperson said. "Such decisions should not be taken to achieve political objectives."

Airspace management decisions about should put safety and stability first, and "should not be made for political ends," Bradley-Jones said in a separate statement.

China views democratically governed Taiwan as its territory despite Taipei's rejection of the claim, and frequently calls the issue a "red line" in its diplomatic relations with other countries.

The small southern African nation of Eswatini is one of only 12 countries to retain formal ties with Chinese-claimed Taiwan. Lai was due to leave on Wednesday for the 40th anniversary of King Mswati III's accession.

The last time a Taiwanese president visited Eswatini, formerly ​known as Swaziland and home to around 1.3-million people, was in 2023, when Tsai Ing-wen made the journey.

Numerous US lawmakers also condemned China for the move and expressed support for Taiwan. The United States does not have formal ties with Taiwan but is its biggest international backer and arms supplier.