Voters headed to the polls on Tuesday in the US states of Mississippi and Michigan, as part of the process to choose Republican and Democratic nominees for the 2016 presidential race.
Trump’s convincing win in Michigan restored his outsider campaign’s momentum and increased the pressure on the party’s anti-Trump forces to find a way to stop his march to the nomination ahead of several key contests next week.
In the Democratic race, Bernie Sanders had a surprise victory in Michigan, but Hillary Clinton increased her lead with a big Mississippi win.
Trump built his victories in Michigan, in the heart of the industrial Midwest, and Mississippi in the Deep South with broad appeal across many demographics. He won evangelical Christians, Republicans, independents, those who wanted an outsider and those who said they were angry about how the federal government is working, according to exit polls.
With 13 percent of precincts reporting, Trump took an early lead in the industrial state with 37.6 percent of the vote, ahead of Kasich with 27.5 percent, while on the Democratic side Sanders had the narrowest of leads over Clinton, with 49.8 to 48.3 percent, according to US media.
In Michigan, Republicans were vying for 59 delegates while Democrats were competing for 130. In Mississippi, 36 delegates were up for grabs in the Democratic contest.
Early results suggested Trump was neck-and-neck with John Kasich in Michigan.
Mr Trump, a businessman with no experience of elected office, leads the polls in Florida, from where he delivered his victory speech on Tuesday night.
“One of the things I am most happy about is the turnout has been just massive… I think it’s the single biggest story in politics today,” he said at a press conference in Jupiter.