WASHINGTON (Reuters) -The United States has reached an understanding with China on how to expedite rare earth shipments to the U.S., a White House official said on Thursday, amid efforts to end a trade war between the world's biggest economies.

During talks in May in Geneva, China committed to removing non-tariff countermeasures imposed against the United States since April 2, although it was unclear how some of those measures would be walked back.

As part of its retaliation to U.S. tariffs announced by President Donald Trump, China added rare earths to its controlled export list.

"The administration and China agreed to an additional understanding for a framework to implement the Geneva agreement," a White House official said on Thursday.

The understanding is "about how we can implement expediting rare earths shipments to the U.S. again", the official said.

U.S. Commerce Secretary Howard Lutnick was quoted as saying by Bloomberg: "They're going to deliver rare earths to us" and once they do that "we'll take down our countermeasures."

China's embassy in Washington did not immediately respond to a request for comment.