A Chinese court on Thursday imprisoned nine people, one whom got a suspended death sentence, on charges of smuggling fentanyl into the United States, in the first such case the two countries had worked on together.

China has faced U.S. criticism for not doing enough to prevent the flow of fentanyl into the United States, and the issue has become another irritant in their ties, already strained by a bruising trade war the two are now working to end.

The joint announcement of the successful action against smugglers, in front of a group of Chinese and foreign reporters invited by the Chinese government, comes as the two countries are expected to be close to signing an interim trade deal.