San Juan (US): Florida Senator Marco Rubio has won the Republican primary election in Puerto Rico, US television projections have said, in a White House race otherwise led by billionaire Donald Trump.
Rubio, 44, had a comfortable lead in the US commonwealth in the Caribbean, according to CNN and NBC News yesterday.
Residents of the island have US citizenship but cannot vote in the US presidential election if they are Puerto Rico residents. Still, they take part in the primary process.
Rubio had about three quarters of the votes, the projections showed, which should hand him the 23 party convention delegates in play.
His campaign was in need of some good news. The son of Cuban immigrants who grew up in Las Vegas and Florida has been struggling in the presidential race.
If confirmed, this would mark just the second outright win for Rubio, who also took Minnesota on Tuesday.
Trump has kept a firm grip on his lead in the Republican race, and called for Rubio to end his presidential bid.
Senator Ted Cruz has emerged as Trump's strongest challenger in weekend primaries with mixed outcomes.
Hillary Clinton, meanwhile, extended her frontrunner status in the Democratic contests, though Senator Bernie Sanders showed he is still in the race with a pair of victories.
Clinton and Sanders compete yesterday in Maine's nominating contest and face off in a televised debate in Flint, Michigan just two days before a crucial primary in that delegate-rich northern industrial state.