Amid escalating tension in Taiwan, US and Chinese officials meet in Zurich and an upcoming meeting between the US and Chinese presidents

The US National Security Adviser and the top Chinese diplomat held talks Wednesday in the Swiss city of Zurich, while the White House said that US President Joe Biden and his Chinese counterpart Xi Jinping plan to hold a "virtual" meeting before the end of this year.

The Zurich meeting came as Taiwanese Defense Minister Chiu Kuo-ching warned that China would be able to launch a "total invasion" of the island by 2025, noting that the Taiwan Strait was experiencing the "most difficult situation" in the last four decades.

The White House said in a statement, "The meeting that brought together US National Security Adviser Jake Sullivan with Director of the Office of the Foreign Affairs Committee of the Communist Party of China Yang Jiechi in Zurich, discussed areas in which the interests of the United States and China require working together to address vital cross-border challenges, and ways Managing risks in our relationship.

He added that during the meeting, Sullivan raised issues of concern, such as China's human rights measures, Xinjiang (East Turkestan), Hong Kong, the South China Sea and Taiwan.

The statement cited Sullivan's affirmation to the Chinese side that Washington will continue to work with its allies and partners, as well as engage with China, to ensure responsible competition.

In a related context, the White House said Wednesday that it was still working on setting a date and details for a meeting between President Joe Biden and his Chinese counterpart Xi Jinping.

"We continue to believe that communication at the president's level is an important part of our efforts to responsibly manage the competition process with China," White House spokeswoman Jen Psaki told reporters.

"We are working out what the meeting will look like, when it will take place, and of course the final details," she added.

On Tuesday evening, Biden and his Chinese counterpart spoke about the escalating tension over the island of Taiwan.

Commenting on the conversation, Biden said in a press statement, "I spoke with Xi about Taiwan. We agree (..) We will abide by the Taiwan Agreement."

"I made it clear that I don't think he should do anything other than stick to the agreement," he added.

On September 23 last, Taiwan announced its application to join the Trans-Pacific Partnership, which led to a new clash with Beijing.

The TPP aims to deepen economic ties between members, by lowering tariffs on agricultural and industrial products, easing investment restrictions and strengthening intellectual property protection.

The Trans-Pacific Partnership, which entered into force in 2018, accounts for about 13% of global GDP, with the participation of 11 countries including Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam.