Washington/Augusta: Donald Trump looked poised to strengthen his lead in the Republican presidential race when 11 states vote on Tuesday, an outcome likely to intensify concerns among party leaders who consider him a usurper.
In the Democratic race, former Secretary of State Hillary Clinton would go a long way toward cementing her path to the nomination if she scores big victories of her own over democratic socialist Bernie Sanders on Super Tuesday.
Opinion polls showed Trump leading in nearly all the states that will hold primary contests or caucuses, many of them in the South. The exception appeared to be Texas, the home state of US Senator Ted Cruz, who enjoyed a narrow lead and was in desperate need of a victory.
Super Tuesday is the biggest single day of state-by-state contests to select party nominees for the Nov. 8 election to succeed Democratic President Barack Obama.
Voting stretches from eastern states to Texas and Minnesota, with the first polls closing at 7 p.m. EST (midnight GMT) in Vermont, Virginia and Georgia and first results expected soon after.
Trump has stunned many in the Republican establishment with campaign pledges 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.
The former reality TV star, who fires up crowds by mocking his rivals and critics, faced heavy criticism this week over his failure to reject white supremacists` support during a CNN interview on Sunday. Trump later disavowed that support, saying he had not heard the questions properly, but his explanations failed to satisfy many.
"If a person wants to be the nominee of the Republican Party, there must be no evasion and no games. They must reject any group or cause that is built on bigotry," House of Representatives Speaker Paul Ryan said in Washington on Tuesday.
Ryan did not mention Trump by name but his target was clear.
With a string of victories on Tuesday, Trump would advance his strong lead over Cruz, US Senator Marco Rubio of Florida, Ohio Governor John Kasich and retired neurosurgeon Ben Carson.
The prospect of a Trump victory has alarmed Republican Party leaders, many of whom do not support his positions and who believe Clinton would easily defeat him in November if she becomes the Democratic nominee.
The crossfire between Trump and establishment Republicans threatens to rip the party apart at a time when it will need to generate momentum behind a prospective nominee. That worries some Republican strategists looking ahead to the nominating convention in July.
"If Trump continues winning, disappointed party elites will need to reconcile with supporting the party nominee," said Tim Albrecht, a Republican strategist in Iowa.
Rubio saw his support increase among Republican voters after a strong debate performance last week, rising to 20 percent from 14 percent, a Reuters-Ipsos poll found. Trump still dominated the field with 42 percent support.
Trump cites his high poll numbers as proof he is not dividing the Republican Party but expanding its ranks.
"We`re getting people into the party we`ve never had before," he told ABC`s "Good Morning America" on Tuesday. "We`re getting Democrats coming in, we`re getting independents coming."
One of those independents, Gwendolyn Beck, was putting up Trump signs across Arlington, one of Virginia`s most liberal areas, when she was confronted by a Sanders supporter carrying a 2-year-old.
"I came here to tell you you`re a terrible person," Mark Blacknell, 40, told Beck before walking into a nearby polling place. He said later he was appalled to see Trump signs being put up in the Washington suburb.
The encounter reflected the acrimonious nature of the 2016 campaign and the divisions it has laid bare among Republicans, adding to the traditional split between the two major American political parties.
CLINTON LEADS IN SOUTH
On the Democratic side, polls show Clinton, who has won three of the first four Democratic contests, with a big lead in six Southern states that have large blocs of black voters, who have been slow to warm to Sanders, a US senator from Vermont.
Sanders has been aiming for wins in five other states on Tuesday - Vermont, neighboring Massachusetts, Oklahoma, Minnesota and Colorado.
One factor helping Clinton is a focus on getting her voters to make their choices early. More than half the delegates needed to secure the Democratic nomination will be chosen in March with contests in 28 states, and more than a third of those have early voting.