The Republican front runner dominates the voting, while Ted Cruz wins three states and Marco Rubio chalks up his first victory.
Steamrolling to a string of Super Tuesday
victories, Republican presidential front runner Donald Trump has vowed
to beat Hillary Clinton in November's election.
Mr Trump swept Alabama, Georgia, Massachusetts and Tennessee, and claimed narrower wins in Virginia, Arkansas and Vermont.
Arch-conservative Texas Senator Ted Cruz breathed a sigh of relief a
Florida Senator Marco Rubio, the Republican party favourite, won his first 2016 contest, the Minnesota caucuses, but was judged to have had a lacklustre night overall.
:: Donald Trump Charges Through Super Tuesday
The tycoon - who has wooed legions of low-income, white voters - told supporters: "Once we get all of this finished, I'm going to go after one person - Hillary Clinton."
:: Clinton Gains Momentum In White House Race
He added: "We have politicians who truly, truly, truly don't know what they're doing."
Mr Trump was flanked by former rival New Jersey Governor Chris Christie, who endorsed him last week.
:: Profile: Donald Trump
In the Democratic race, front runner Hillary Clinton won seven states, while her rival, Bernie Sanders, took four.
Ohio Governor John Kasich and retired neurosurgeon Ben Carson have still not won any contests for the Republican nomination.
The White House hopefuls are all vying to win delegates who will vote for them at the parties' conventions in July.
:: Profile: Ted Cruz
After Super Tuesday, Mr Trump was leading with 274
delegates, Mr Cruz had 149, Mr Rubio was on 82, Mr Kasich 25 and Mr
Carson eight.
Some 1,237 delegates are needed for a candidate to win the Republican nomination.
:: Profile: Marco Rubio
Party leaders fear Mr Trump will ruin their chances of recapturing the White House after President Barack Obama's two terms.
The tycoon has repeatedly courted controversy with inflammatory outbursts.
But on Tuesday he sought to defuse claims he is too divisive, insisting he was a "unifier" and a "common-sense conservative" who would grow the party.
Mr Cruz, meanwhile, argued he is the only Republican who can beat "profane and vulgar" Mr Trump.
The Texas senator "prayerfully" suggested candidates who have not yet won a state bow out.
For Mr Rubio, the 15 March primary in his home state of Florida is a now must-win.
Mr Trump currently has a double-digit lead there.
Some 1,237 delegates are needed for a candidate to win the Republican nomination.
:: Profile: Marco Rubio
Party leaders fear Mr Trump will ruin their chances of recapturing the White House after President Barack Obama's two terms.
The tycoon has repeatedly courted controversy with inflammatory outbursts.
But on Tuesday he sought to defuse claims he is too divisive, insisting he was a "unifier" and a "common-sense conservative" who would grow the party.
Mr Cruz, meanwhile, argued he is the only Republican who can beat "profane and vulgar" Mr Trump.
The Texas senator "prayerfully" suggested candidates who have not yet won a state bow out.
For Mr Rubio, the 15 March primary in his home state of Florida is a now must-win.
Mr Trump currently has a double-digit lead there.
