The Chinese government said it will extend a suspension of retaliatory tariffs on U.S. autos and include the opioid fentanyl in a list of controlled substances, two steps that could generate a positive atmosphere for trade negotiations due to resume this week.

Beijing temporarily scrapped the 25 percent tariff imposed on vehicles as a tit-for-tat measure on Jan. 1, after the White House delayed a rise in tariffs on $200 billion of products that had been due that day. An end date for the extended suspension will be announced separately, the Ministry of Finance said.

The move seeks to “continue to create a good atmosphere for China-U.S. economic and trade talks” and is a “positive response” to the U.S. decision to delay tariff increases, the Ministry of Finance said in a statement on Sunday. Vice Premier Liu He is due to return to Washington this week as negotiators finalize the details of an agreement text.

Chinese officials also pledged to tighten regulation on fentanyl on Monday, a promise Xi made to Trump at a December meeting in Argentina. The inclusion of the drug as a controlled substance in a category of non-medicinal narcotic drugs and psychotropic substances will start May 1, according to the China National Narcotics Control Commission.

China touted “new progress” in talks after U.S. Trade Representative Robert Lighthizer and U.S. Treasury Secretary Steven Mnuchin visited Beijing last week. Both sides have been working line-by-line through the text of an agreement that can be put before President Donald Trump and his Chinese counterpart Xi Jinping, people familiar said earlier.