Amphibious training exercises led by a group of visiting Marine Raiders were described as “routine” by Taiwan’s Naval Command. It marked the first public acknowledgement of American troops in Taiwan since Washington and Taipei ended formal diplomatic ties in 1979.

Soldiers belonging to the Taiwan Marine Corps will receive four weeks of training under the Raiders—a special operations force—learning amphibious assault operations and speedboat infiltration techniques, Taiwan’s United Daily News reported.

The training sessions will take place at Tsoying base in Taiwan’s southwestern port city of Kaohsiung, the paper said.

The Raiders are believed to have arrived in Taiwan as early as October 26, but observed two weeks of quarantine as part of the island’s measures to contain COVID-19.

The U.S. Marines are the first allied troops to conduct joint military training with Taiwan since the coronavirus outbreak began eight months ago, the newspaper said.

“In order to maintain regional peace and stability, routine security cooperation and exchanges between the militaries of Taiwan and the United States are proceeding as usual,” the Taiwanese Navy said in a statement on its website.

Navy Command said it would not give any details about the training exercises.

The exceedingly rare acknowledgement of U.S. boots in Taiwan comes just days after American television networks called the presidential election for Democrat Joe Biden.

Although President Donald Trump has yet to concede and his administration continues to dispute the outcome, concern has set in among Taiwanese residents who were overwhelmingly in favor of a Trump re-election because of his hardline stance on China, as well as the multibillion-dollar arms deals struck with President Tsai Ing-wen’s government.

In the latest round of weapons sales, which were announced by the Pentagon on Election Day last Tuesday, the democratic island purchased $600 million of armed Reaper drones.

However, despite neither Washington nor Taipei having officially acknowledged the presence of U.S. troops in Taiwan for more than 40 years, military exchanges between the two were a regular occurrence before COVID-19, according to United Daily News.

Observers from Washington were invited for Taiwan’s yearly Han Kuang military exercises, while U.S. Army Special Forces were invited for annual joint sessions with Taiwan’s equivalent Army Aviation and Special Forces Command.

The Green Berets are involved in Operation Balance Tamper, which takes place in the mountainous regions of central Taiwan, the newspaper said.

Also present every year are the U.S. Navy SEALs, who train Taiwanese frogmen off the coast of Taiwan’s Penghu Islands in Operation Flash Tamper.