Visiting U.S. Health and Human Services Secretary Alex Azar was welcomed by Republic of China, or Taiwan, President Tsai Ing-wen Monday as head of the highest-level U.S. delegation to visit the country since the U.S. severed diplomatic ties in 1979 in favor of China.

China, on the other hand, "greeted" the Donald Trump administration official and his entourage with a show of force. It sent air force fighter planes briefly into Taiwan's portion of a 16-kilometerwide median line in the Taiwan Strait. China considers Taiwan a renegade province.

The incursion by fighters of the People's Liberation Army Air Force occurred shortly before Azar and Tsai met. Taiwan's ministry of defense said its planes drove away the PLAAF aircraft. It said the incursion was the third only by the PLAAF since 2016.

The Trump administration is billing Azar's visit as a bid to boost economic and public-health cooperation with Taiwan. Azar's visit is to support Taiwan's international role in fighting the COVID-19 pandemic.

Political observers said the Trump administration had made no mention of the U.S. trying to emulate Taiwan's successful formula in coping with the pandemic. They said Azar's visit was actually a re-election stunt by President Trump - who consistently reminds American voters COVID-19 originated in China. Trump refers to the disease as the "China virus."

The U.S. remains the worst affected country in the world with 5.2 million cases and 166,000 deaths. Taiwan, which has been praised as an example of what a country can do has 480 cases and seven deaths.

"It's a true honor to be here to convey a message of strong support and friendship from President Trump to Taiwan," said a masked Azar.

"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."

Tsai said Taiwan saw Azar's visit as "a huge step forward in antipandemic collaborations between our countries." She said Taiwan was especially grateful for U.S. support that allowed its attendance at the World Health Assembly. The assembly is the decision-making body of the World Health Organization. Taiwan isn't a member of organization as a result of objections from China.

Tsai said political considerations "should never take precedence over the rights to health. The decision to bar Taiwan from participating in the (assembly) is a violation of the universal rights to health."