Republican Donald Trump rolled up seven wins on 1 March, as the front-runner took a step towards capturing the Republican party nomination on the 2016 campaign's biggest day of state-by-state primary voting.

The real-estate mogul turned his sights on Democratic frontrunner Hillary Clinton after she also took seven wins, with Trump promising to "go after" Clinton. Trump's rival Ted Cruz, a US senator from Texas, won his home state and neighbouring Oklahoma, bolstering his argument he had the best chance to stop the controversial Trump.

Trump and Clinton each won seven states on Super Tuesday, when 12 states were voting. Trump racked up wins in Alabama, Arkansas, Georgia, Massachusetts, Tennessee, Vermont and Virginia. Clinton snatched victories in Alabama, Arkansas, Georgia, Massachusetts, Tennessee, Virginia and Texas.

Selecting party nominees for the 8 November election to succeed Democratic President Barack Obama saw voting take place from eastern states to Texas and Minnesota.

"I am a unifier," Trump told reporters in Palm Beach, Florida, dismissing concerns about his rhetoric. "Once we get all this finished, I'm going after one person – Hillary Clinton."

"We have expanded the Republican Party. When you look at what's happened in South Carolina and you see the kind of numbers that we got in terms of extra people coming in, they came from the Democratic Party. They're long-time Democrats and they were never going to switch and they all switched," he said.

Trump has worried many in the Republican establishment with proposals such as building a wall along the US southern border with Mexico, deporting 11 million illegal immigrants and slapping a temporary ban on Muslims entering the country.