BEIJING — U.S. Sen. Steve Daines, a strong supporter of President Donald Trump, is visiting Beijing as the U.S. and China swap tariff threats and harsh words over each others’ handling of the illegal trade in fentanyl.

Daines, a Republican from Montana, arrived in the Chinese capital on Thursday after meeting top leaders in Vietnam, according to social media posts by him and the U.S. Embassy in Beijing.

He said on X earlier this week that he would be talking with Chinese officials about curbing the production and distribution of fentanyl and “the need to reduce the trade deficit and ensure fair market access for our Montana farmers, ranchers and producers.”

His office said ahead of the trip that he is coordinating closely with the White House and will be “carrying President Trump’s America First agenda.”

Daines previously worked as an executive for U.S. companies in China and served as a go-between during Trump’s first term in office when tariffs were also a major issue. He is the first member of Congress to visit Beijing since Trump took office in January.

U.S.-China tensions have spiked as the U.S. imposed 20% duties on Chinese goods, drawing retaliatory tariffs of 15% on U.S. farm goods from China this past week. The U.S. accuses China of doing too little to stop the export of precursor materials for fentanyl, a highly potent opiate blamed for tens of thousands of deaths in the U.S.

China responded with a report detailing its efforts to control the illegal trade in fentanyl, specifically the ingredients for the opioid that are made in China, and the foreign minister blasted the U.S. for responding to Beijing’s goodwill with tariffs.

The report said that China and the U.S. have held multiple high-level meetings since early last year to promote cooperation, and that its Narcotics Control Bureau holds regular exchanges with the U.S. Drug Enforcement Agency.

China is committed to cooperation, the report said, “but firmly opposes the U.S. imposition of unlawful sanctions and unreasonable pressure on China on the pretext of responding to fentanyl-related issues.”