WASHINGTON (Reuters) - White House economic adviser Larry Kudlow demurred on Friday when asked if U.S. President Donald Trump would delay or stop the imposition of tariffs on $300 billion worth of Chinese goods if China took some positive actions.

“I have not heard anything definitive,” Kudlow said in an interview with Fox Business Network.

“The president’s not satisfied with the progress on the trade deal,” Kudlow said.

Trump said in a post on Twitter on Thursday that, because of lack of progress in U.S.-China trade talks and lack of movement to stem sales of the synthetic opioid fentanyl here, he would impose a 10% tariff on $300 billion worth of Chinese imports.

Fentanyl is an opioid painkiller 50 times more potent than heroin, and has a central role in a devastating U.S. opioid crisis. In the United States, fentanyl and all of its analogues are controlled substances subject to strict regulation.

Kudlow said in a separate interview with Bloomberg TV that the White House did not think a tariff on additional Chinese goods would significantly affect U.S. consumers.

“Our view is any impact on U.S. consumers is ... miniscule, and we have models to show that,” Kudlow told Bloomberg.

The United States and China have been locked in trade tensions marked by tit-for-tat tariffs. The trade war has roiled global markets and economies and disrupted supply chains.