WASHINGTON/LONDON (Reuters) - The United States on Friday rejected a formal request from Britain for the extradition of a U.S. diplomat’s wife who left the country last year after a road collision that killed 19-year-old Briton Harry Dunn.

Harry Dunn's mother Charlotte Charles poses in front of a banner outside the Buckingham Palace as people demonstrate during U.S. President Donald Trump's visit for NATO summit, in London, Britain December 3, 2019. REUTERS/Dylan Martinez

British prosecutors are seeking the extradition of Anne Sacoolas over the crash last August in which Dunn was killed while riding his motorbike.

“Following the Crown Prosecution Service’s charging decision, the Home Office has sent an extradition request to the United States for Anne Sacoolas on charges of causing death by dangerous driving,” a UK Home Office spokesman said in a statement on Friday.

“This is now a decision for the U.S. authorities.”

A U.S. State Department spokesman said Washington would not grant the request.

“Under the circumstances of this case, we strongly believe that an extradition request would be highly inappropriate,” the spokesman said in a statement.

“The United States has been clear that, at the time the accident occurred, and for the duration of her stay in the UK, the driver in this case had status that conferred diplomatic immunities,” the statement said.

“The use of an extradition treaty to attempt to return the spouse of a former diplomat by force would establish an extraordinarily troubling precedent,” it said.

Dunn’s family has said Sacoolas was driving on the wrong side of the road at the time of the crash near an air force base in central England used by the U.S. military.

Sacoolas, 42, was given diplomatic immunity and left Britain shortly after the accident. Her lawyer has said that she would not return voluntarily to Britain to possibly face jail for “a terrible but unintentional accident.”

British Prime Minister Boris Johnson has said Sacoolas was wrong to use diplomatic immunity to leave Britain and has urged U.S. President Donald Trump to reconsider the U.S. position.

Dunn’s parents met Trump at the White House in October. Trump hoped to persuade them meet to Sacoolas, who was in the building at the same time, but they declined.