Charleston, March 6 -- Former US Ambassador to the United Nations Nikki Haley will suspend her presidential campaign on Wednesday, according to a source familiar with her plans, ensuring that Donald Trump will win the Republican nomination and once again face Democratic President Joe Biden in November's election.

Haley will give a speech at 10 am local time to address her future in the race, the source said, but she will not be giving an endorsement.

Haley lasted longer than any other Republican challenger to Trump but never posed a serious threat to the former president, whose iron grip on the party's base remains firm despite his multiple criminal indictments.

The rematch between Trump, 77, and Biden, 81 - the first repeat US preside...