China is willing to do more to address White House concerns about illicit fentanyl trade, but it will be “a different thing” if ongoing debate over the drug facilitates more U.S. tariffs on the world’s second largest economy, an official from the Chinese Ministry of Foreign Affairs told reporters Wednesday.

Washington should have “said a big thank you” to China on what it has done to restrict fentanyl trade in the U.S., the official said via an official English translation, claiming the White House did not appreciate the effort and instead raised duties on Chinese goods twice this year over the drug.

Since taking office in January, U.S. President Donald Trump has increased tariffs on Chinese goods by 20% on the basis of the country’s alleged role in the U.S. fentanyl crisis. The addictive drug, precursors to which are mostly produced in China and Mexico, has led to tens of thousands of overdose deaths each year in the U.S.

The White House did not immediately respond to a CNBC request for comment.

Earlier this month, the Chinese government published a white paper to publicize its efforts to curtail the production and export of fentanyl precursors over the last few years. The official did not respond directly to a question on whether China would stop its recent efforts to restrict such trade.