U.S. and Chinese officials held a "working-level" call Thursday evening in which Beijing said it was making progress in restricting outbound fentanyl shipments, according to three sources familiar with the matter, homing in on a personal policy focus of President Donald Trump as it tries to get the White House to rollback tariffs.

In the call, these sources said, Chinese officials again reiterated a desire for relief on tariffs, with 15% tariffs set to hit $112 billion goods on Sunday, and existing tariffs to rise on an additional $250 billion in goods a month later.

It's unclear whether President viewed the evidence China provided – which could not be learned by CNBC – as sufficient progress. As he departed the White House for Camp David on Friday evening, he told reporters the next round of tariffs is still on.

It's unclear whether the level of detail provided by China on halting fentanyl exports would be enough to get President Trump to roll back the tariffs that, according to aides, he believes are his most effective policy tool.

Fentanyl has been a high priority for the White House as it moves to combat the opioid crisis.

Stopping shipment of the drug from China to the U.S. was a focal point of conversation for the two leaders when they met at the G-20 in Buenos Aires in late 2018.

At a bilateral dinner, President Xi Jinping committed to reclassifying fentanyl and related drugs as "controlled substances," and subjecting anyone caught making or selling the drugs to maximum penalty.

Trump has accused Xi of not doing enough since then to stop the flow of illicit drugs to the US.

In a briefing this week, China's Foreign Ministry said it's "groundless and false" that China is the main source of fentanyl in the U.S., and that the U.S. isn't doing enough to stem demand for the drug among domestic users.

"With 5% of the world's total population, the U.S. consumes 80% of the global opioid medication," spokesperson Geng Shuang told reporters on Aug. 29. "If the US really wants to solve its fentanyl problem, it should put its own house in order."

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

The U.S. Trade Representative and the Treasury Department declined to comment.