US Health and Human Services Secretary Alex Azar arrived in Taiwan on Sunday in the highest-level visit by an American Cabinet official since the break in formal diplomatic relations between Washington and Taipei in 1979.

Beijing has already protested Azar's visit as a betrayal of US commitments not to have official contact with the island. China claims Taiwan as its own territory, to be brought under its control by military force if necessary.

Azar is due to meet with the island's independence-leaning President Tsai Ing-wen along with health officials during a three-day visit aimed at highlighting cooperation in the fight against the coronavirus.

Taiwan's government-run health care system has been credited with keeping the number of coronavirus cases to under 500 with just seven deaths, despite its close proximity to China where the virus originated.

China sees Taiwan as a key irritant in its troubled relationship with Washington, with whom it is also at odds over trade, technology, the South China Sea and China's response to the virus pandemic.

The US maintains only unofficial ties with Taiwan in deference to Beijing, but is the island's most important ally and provider of defence equipment.

Azar is the first health secretary to visit Taiwan and the first Cabinet member to visit in six years. In 2014, then-Environmental Protection Agency administrator Gina McCarthy visited Taiwan, sparking protests from Beijing.

Azar's office said he will hold discussions on COVID-19, global health and Taiwan's role as a supplier of medical equipment and technology Azar's visit was facilitated by the 2018 passage of the Taiwan Travel Act, which encouraged Washington to send higher-level officials to Taiwan after decades during which such contacts were rare and freighted with safeguards to avoid roiling ties with Beijing.

China has cut contacts with Tsai over her refusal to recognise China's claim to the island and has brought increasing diplomatic, economic and military pressure against her, including by poaching away several of its remaining diplomatic allies and excluding it from international gatherings including the World Health Assembly. That, in turn, has increased already considerable bipartisan sympathy for Taipei in Washington and prompted new measures to strengthen governmental and military ties.

Also Sunday, Taiwanese Foreign Minister Joseph Wu met with the first representative of Somaliland to the island ahead of the territory's opening of a representative office in Taipei.

Wu earlier tweeted that Mohamed Omar Hagi Mohamoud had “braved Chinese pressure” — a reference to reports that China had sought to block relations between Taiwan and the region on the Horn of Africa that broke from the rest of Somalia but is not recognized by the United Nations as an independent country.

“The fact 'sovereignty & friendship aren't for sale' deserves international recognition,” Wu tweeted.

On his arrival, Mahamoud tweeted that “We are ready to establish good relations with all countries - those we share values of democracy are special."