The governor of the Northern Marianas, Ralph Torres, has endorsed the billionaire Donald Trump ahead of the territory's Republican caucuses today.

Photo: CNMI Republican Facebook

As an unincorporated commonwealth of the United States, the Northern Marianas is unable to vote in November's presidential election, but is able to participate in the candidate selection process.

The territory's Republicans will vote for their nine delegates tonight, who will then go to the party's National Convention in July to nominate a presidential candidate.

In a statement, Governor Ralph Torres said he had initially supported Ben Carson, who bowed out of the race last month.

He said he has now thrown his support behind Mr Trump, saying he heard nothing from the other Republican candidates and that Mr Trump has promised to appoint a White House special assistant for the territories.

Mr Trump currently has the lead in the delegate count for the Republican nomination.

On Saturday, the territory's Democrats endorsed Hillary Clinton in their caucus.