Beijing expressed its anger at a visit by Germany's education minister to Taiwan on Tuesday, describing it as "vile", while a source at Berlin's foreign office responded by saying the trip did not deviate from Germany's "one China" policy.
China views democratically governed Taiwan as its own territory and has ramped up military, political and economic pressure to assert those claims. The politically sensitive visit is taking place as Berlin is reviewing its previously close ties with China.
In January, a visit to Taiwan by a delegation of high-ranking lawmakers from the liberal Free Democrats (FDP), the smallest party in Chancellor Olaf Scholz's three-way coalition, also led to protests from Beijing.
Education Minister Bettina Stark-Watzinger, also of the FDP, said at the signing of a technology cooperation agreement with Taiwan's National Science and Technology Council Minister Wu Tsung-tsong that it was "extremely important to my ministry and I to promote cooperation with like-minded partners".
"This arrangement stands for enhancing cooperation on the basis of the democratic values transparency, openness, reciprocity and scientific freedom, to only name a few," she said in Taipei on Tuesday.
"It is a great pleasure and honour for me to be the first minister heading a specialist government department to visit Taiwan in 26 years," she added. "Taiwan, with its excellent research institutions, is a highly esteemed partner."
In Beijing, Chinese Foreign Ministry spokesman Wang Wenbin said it had filed a strong protest with Germany about her "vile conduct".
Germany should "immediately stop associating and interacting with Taiwan independence separatist forces, immediately stop sending wrong signals to Taiwan independence separatist forces, and immediately stop using the Taiwan issue to interfere in China's internal affairs", Wang told a daily news briefing.
A source at the German foreign office said Berlin had taken note of the Chinese response but that Stark-Watzinger's trip was in line with its "one China" policy, which acknowledges that Taiwan is an inalienable part of China.
Germany, like most countries, has no formal diplomatic ties with Taiwan, though it does maintain a de facto embassy in Taipei.
Given the sensitivity of the trip, Stark-Watzinger is not scheduled to meet Taiwan President Tsai Ing-wen.
In a departure from the policies of Germany's former chancellor, Angela Merkel, Olaf Scholz's government is developing a new China strategy to reduce dependence on Asia's economic superpower, hitherto a vital export market for German goods.
Responding to a question from a reporter, Stark-Watzinger said: "The federal government's China strategy remains unchanged. To that extent, this visit today is not connected with that."
(Reporting by Fabian Hamacher; Additional reporting by Yew Lun Tian in Beijing; Writing by Ben Blanchard. Editing by Gerry Doyle and Tomasz Janowski)