Hsiao Bi-khim says she is not an ambassador, but like one, after observers point out detail in her online bio

Clarification comes at a time of heightened tensions between Washington and Beijing over the self-ruled island

Taiwan’s representative to the US Hsiao Bi-khim has clarified that she is not an official ambassador, despite describing herself as such in her Twitter online bio at a time of increasing criticism from Beijing over official exchanges between Washington and Taipei.

Hsiao responded to media attention over the bio – which describes her as “Taiwan ambassador to the US” – in a tweet on Monday which acknowledged that her official title was “representative” of the Taipei Economic and Cultural Office (TECO), which functions as unofficial embassy for the island.

“Sorry to disappoint so many supporters, but Taiwan ambassador is what many call me and also my job description,” she added. There was no change to the bio on the account, which is described as personal.

The US does not have formal ties with the self-ruled island and Beijing – which regards Taiwan as a renegade province, to be returned to the mainland by force if necessary – has threatened to take action against moves that undermine its claims to sovereignty.

Tensions, already heightened as a result of fraying cross-strait relations and ongoing disputes between China and the US, have been worsened by high-profile meetings between senior Washington and Taipei officials.

An ambassadorial rank for Hsiao would signal an elevation of relations to a formal diplomatic level which Beijing would certainly see as a crossing of its political “red lines” on Taiwan.

Hsiao, who was posted to the US at the end of July, also added a clarification to her official Facebook account. She said it was undeniable that the US policy framework around the one-China policy still existed, but that her practical work was no different from that of other embassies.

“Because Taiwan’s situation is so difficult, my workload and the frequency of my interactions with the US are more complicated than that of other countries’ ambassadors, so ‘ambassador’ is not only a descriptor for my current job but is how many friends in the US refer to me,” she said.

Taiwanese president Tsai Ing-wen on Sunday told reporters that Hsiao would always work hard for the island “no matter what her title is”.

Ma Xiaoguang, spokesperson for Beijing’s Taiwan Affairs Office, was quoted earlier by Chinese state media as slamming the ruling Democratic Progressive Party in Taiwan for “wantonly disrupting cross-strait relations”, and reiterating opposition to official relations between Taiwan and other countries.Last week the People’s Liberation Army conducted military exercises near the Taiwan Strait during a visit to the island by US undersecretary of state Keith Krach – the most senior State Department official to travel to the island in 41 years. US health secretary Alex Azar visited Taiwan in August and attracted a similar response.

Beijing also protested after US ambassador to the United Nations Kelly Craft held a lunch meeting last Wednesday with her de facto counterpart James Lee Kuang-jang, director of the TECO office in New York and head of Taiwan’s United Nations Affairs Task Force in the city.

Titles for Taiwan’s top diplomats have been the source of scrutiny in the past. Taiwan’s foreign ministry clarified in September 2012 that, while it referred to all its senior diplomatic envoys as “ambassadors” internally, their official titles were as “representatives” in countries that did not have formal diplomatic relations with Taiwan.