BEIJING (Kyodo) -- U.S. Navy Rear Adm. Michael Studeman visited Taiwan over the weekend, Taiwanese media reported Monday, prompting China to lambast the visit.
Studeman's unannounced visit on Sunday comes as the U.S. government under President Donald Trump has sought closer ties with the self-governed island, including sending several senior officials since this summer.
China "firmly opposes" any form of official exchanges between Washington and the self-governed island, Foreign Ministry spokesman Zhao Lijian told reporters, adding that it has lodged a diplomatic protest with the United States.
China urges the United States to "stop enhancing" its substantive relationship with Taiwan, "so as not to seriously damage Sino-U.S. relations as well as peace and stability across the Taiwan Strait," Zhao also said.
Studeman is currently director for intelligence at the U.S. Indo-Pacific Command in Honolulu, Hawaii, according to its website.
Reuters news agency reported earlier that the admiral made an unannounced visit to Taiwan, citing two sources including a Taiwanese official familiar with the situation.
Taiwan's Foreign Ministry declined to give details due to the visit being undisclosed.
Taiwan and mainland China have been separately governed since they split in the wake of a civil war in 1949. Their relationship has deteriorated under the government of independence-leaning Tsai Ing-wen, who has served as Taiwan's president since 2016.
Washington switched its diplomatic recognition from Taipei to Beijing in 1979, but the Trump administration has been boosting ties with the democratic island by taking such actions as selling it weapons packages.
In August, U.S. Health and Human Services Secretary Alex Azar became the most senior U.S. official to visit Taiwan since 1979. The following month, Keith Krach, U.S. undersecretary of state for economic growth, energy and the environment, traveled to the island.
On Friday, the United States and Taiwan held the first meeting of their new economic dialogue as the Trump administration has continued to give vocal support to the island.
Moreover, the head of the U.S. Environmental Protection Agency is also likely to become the country's third senior official to visit Taiwan since August, media reports said Friday, in a move that would further exacerbate their already strained relations with China.
China, meanwhile, has recently carried out military drills in the Taiwan Strait and surrounding waters, amid persistent concern that the Communist-led government will try to achieve its cherished goal of reuniting the island with the mainland, by force if necessary.