US Republican presidential candidate Nikki Haley will announce her withdrawal from the presidential race today, The Wall Street Journal reports.

According to the publication, she will also urge her supporters to vote for the last Republican candidate, Donald Trump.

After Haley's withdrawal from the race, the former president will have no rivals.

It's worth noting that Donald Trump won the Republican primaries - these are the results of Super Tuesday, when voting took place in 15 states at once. Nikki Haley has an advantage in only one state, the small Vermont.