Hillary Clinton and Donald Trump have continued to win new states, now taking Arizona.
The issue of immigration loomed large in Arizona, the biggest prize in the latest round of contests.
Polls showed that Donald Trump’s anti-immigration message resonated with Arizona’s conservative voters.
With the state’s growing Latino population, Democratic front-runner Hillary Clinton continued her success by courting minority voters.
Keeping his campaign in the race, rival Democrat Bernie Sanders decisively won caucuses in two smaller states, Idaho and Utah.
During a victory speech in Seattle, Hillary Clinton addressed the terrorist attacks in Brussels on March 22, pushing back against the Republican candidates’ response to the bombings.
Meanwhile, Donald Trump reiterated his plan to ban Muslims from travelling to US and suggested that the US should torture terrorism suspects.
The Republican primary in Arizona was a winner-take-all race, adding 58 delegates to Donald Trump’s sizable lead.
Donald Trump’s win complicates efforts by Ted Cruz and Ohio Governor John Kasich to stop him from securing a majority of delegates.
If Donald Trump falls short in the delegate count, the party could hold a brokered or contested convention where party leaders, not voters, choose the nominee.
However, that scenario is looking less likely as Donald Trump continues to win states.
Arizona residents’ preference for early voting, with many mailing in their ballots, may have affected the race.
Florida Senator Marco Rubio, who left the race on March 15, has secured more than 70,000 votes thus far.
As the final voters headed to the polls on March 22, the Republican race took another nasty turn.
Mistakenly believing the Cruz campaign had produced an attack advert about his wife Melania, DonaldTrump on Twitter threatened to “spill the beans” on Ted Cruz’s wife, Heidi.
Ted Cruz responded saying his campaign did not produce the advert, calling Donald Trump “classless” and a “coward”.