TAIPEI (Taiwan News) — China will respond to the reported visit of a U.S. Navy admiral to Taiwan, China’s Foreign Ministry said on Monday (Nov. 23).

A two-star navy admiral overseeing U.S. military intelligence in the Asia-Pacific region made an unannounced visit to Taiwan on Sunday (Nov. 22), Reuters reported. Neither Taiwan’s Ministry of National Defense (MND) nor the U.S. Pentagon have confirmed the trip.

Taiwan’s Ministry of Foreign Affairs (MOFA) did confirm on Sunday that a U.S. official had arrived in the country but did not provide any further details, adding the visit has not been made public.

China Foreign Ministry Spokesman Zhao Lijian (趙立堅) said at a press conference in Beijing that China “resolutely opposes” any form of exchanges between U.S. and Taiwanese officials, reported Reuters. Zhao told reporters that China urges the U.S. to recognize the extreme sensitivity of the Taiwan “issue.”

“The Chinese side will, according to how the situation develops, make a legitimate and necessary response,” he added without giving further details, according to Reuters.

Sources speaking on condition of anonymity told Reuters that Rear Admiral Michael Studeman, director of J2, which is in charge of intelligence, at the U.S. military’s Indo-Pacific Command was visiting Taiwan. Under the Donald Trump administration, Washington has increased high-level visits to Taiwan.

In August, Health and Human Services Secretary Alex Azar became the highest-ranking U.S. Cabinet official to visit the country since the severing of diplomatic relations between Taipei and Washington in 1979. Azar was then followed by Under Secretary of State Keith Krach, who attended a memorial serviced for late President Lee Teng-hui (李登輝) in September.

On Dec. 5, Andrew Wheeler, head of the U.S. Environmental Protection Agency, is expected to lead a 10-person delegation to Taiwan for a three-day visit to talk about marine litter, air quality, and children’s issues.