The Taiwanese government said on Monday that China deployed fighter jets that briefly crossed the midline of the Taiwan Strait into the country, The South China Morning Post reported. The move came while United States Secretary of Health and Human Alex Azar was visiting Taiwan, and offered American support to the region.

The Taiwanese air force said its missiles tracked the fighter jets and “drove them out”. China, which had promised unspecified retaliation to the trip, condemned Azar’s visit, Reuters reported. It flew J-11 and J-10 fighter aircraft briefly onto Taiwan’s side of the strait that separates it from China, around 9 am local time (6.30 am Indian Standard Time). China claims sovereignty over Taiwan.

“The Air Force Command expresses that the deliberate intrusion and move that damages the Taiwan Strait situation has seriously hurt regional safety and stability,” Taiwan’s Ministry of Defence said. “It should be stressed that Taiwan’s military has fully grasped all developments near the Taiwan Strait and airspace, and can respond appropriately to any changes in the enemy’s situation to ensure national security.”

Azar met Taiwanese President Tsai Ing-Wen. This was the highest-level visit by a US Cabinet official to Taiwan since 1979, when Washington began to recognise the People’s Republic of China, instead of the Republic of China (Taiwan), as representing the country. The United States said Azar’s trip was intended to convey a “message of strong support” to Taiwan, and compliment its leadership for its handling of the coronavirus pandemic.

“Taiwan’s response to Covid-19 has been among the most successful in the world, and that is a tribute to the open, transparent, democratic nature of Taiwan’s society and culture,” Azar told Tsai. The country has reported just 480 coronavirus cases and seven deaths so far, with most infections being imported.

On the other hand, United States President Donald Trump has repeatedly clashed with China over the pandemic, accusing Beijing of responsibility for it. He has called Covid-19 the “China virus” and claimed that Beijing’s “secrecy, deceptions” led to the contagion spreading all over the world.