US diplomat

At a televised event with university students in the Tonga capital Nuku’alofa on Saturday, Sherman noted the countries had fought alongside each other since World War Two, some three decades before establishing formal relations.

She said while the countries shared values of religious freedom and concern for human rights, the U.S. also considered Tonga strategically important.

The staffer was allegedly involved in an incident on 12 March, but police were unable to question him after the embassy declined their request.

New Zealand then asked the US to remove the man, who American officials confirmed had left on Saturday.

Police have refused to give further details of the allegations.

However, New Zealand Radio reported the man - who has not been named - had left the country with a broken nose and a black eye.