Donald Trump aimed to crush the White House hopes of two Republican rivals in Tuesday's primary elections in Florida and Ohio, the biggest prizes on a delegate-rich day of voting that could clarify the nomination fights in both parties. Hillary Clinton hoped to pad her delegate lead in the Democratic race.
Anxious to block Trump's path were Ohio Gov. John Kasich and Florida Sen. Marco Rubio, each in need of a home-state win to stay in the GOP race. Kasich was locked in a close contest with Trump in Ohio, while Rubio appeared to be fading in recent Florida preference polls.
Kasich has largely avoided criticizing his rivals during the tumultuous primary season, but he said he would have plenty to say about Trump after Tuesday's elections. He said he felt a need "to point out things that have been deeply disturbing."
Illinois, Missouri and North Carolina were also voting.
For Democrats, the primaries offered front-runner Clinton a chance to solidify her lead over Bernie Sanders, while the Vermont senator was hoping to build on a surprising win last week in Michigan.
Reprising a theme that helped propel that victory, Sanders has pounded Clinton's past support for trade deals such as the North American Free Trade Agreement, which he says has been a job-killer in the U.S.
"When it came down whether you stand with corporate America, the people who wrote these agreements, or whether you stand with the working people of this country, I proudly stood with the workers," Sanders said during a campaign stop Tuesday in Ohio. "Secretary Clinton stood with the big money interests."
According to early exit polls, Democratic voters were more likely to describe Sanders as honest, but more likely to describe Clinton's policies as realistic.
Clinton's campaign was bracing for potentially close contests in the Midwest, but she was bullish about her prospects in Florida, the day's biggest prize.
Campaigning Tuesday in North Carolina, Clinton said "the numbers are adding up in my favor." She signaled an eagerness to move on to a possible general election showdown with Trump, saying he's laid out a "really dangerous path" for the country.
Trump entered Tuesday's primaries embroiled in one of the biggest controversies of his contentious campaign. The GOP front-runner has encouraged supporters to confront protesters at his events and is now facing accusations of encouraging violence after skirmishes at a rally last week in Chicago.
The vibe at Trump's events has deepened the concern over his candidacy in some Republican circles. Rubio and Kasich have suggested they might not be able to support Trump if he's the nominee, an extraordinary stance for intraparty rivals.
Senate Majority Leader Mitch McConnell, R-Ky., said he spoke with Trump about the rally incidents in a phone call Tuesday morning.
"I took the opportunity to recommend to him that no matter who may be triggering these violent expressions or conflicts that we have been seeing at some of these rallies, it might be a good idea to condemn that and discourage it no matter what the source of it is," McConnell said.
Trump's closest competition so far has come from Texas Sen. Ted Cruz, who is keeping close to the businessman in the delegate count. Cruz has been urging Rubio and Kasich to step aside and let him get into a one-on-one race.
Even before Tuesday's results, however, a group of conservatives was planning a meeting to discuss options for stopping Trump, including at a contested convention or by rallying around a third-party candidate. While such no candidate has been identified, the participants in Tuesday's meeting planned to discuss ballot access issues, including using an existing third party as a vehicle or securing signatures for an independent bid.
A person familiar with the planning confirmed the meeting on the condition of anonymity because they were not authorized to discuss the gathering by name.
If Trump sweeps Tuesday's contests, he'll cross an important threshold with more than 50 percent of the delegates awarded so far.
Despite concerns from party leaders, Republican voters continue to back Trump's most controversial proposals, with two-thirds of those who participated in GOP primaries Tuesday saying they support temporarily banning Muslims from the United States.
The exit polls were conducted by Edison Research for The Associated Press and television networks.
Trump won easily in the Northern Mariana caucus on Tuesday, picking up nine delegates. That gave him 469 to 370 for Texas Sen. Ted Cruz, 163 for Rubio and 63 for Kasich. It takes 1,237 to win the GOP nomination.
Entering Tuesday, Clinton had 768 pledged delegates compared to 554 for Sanders, according to an analysis by The Associated Press. Overall, Clinton holds 1,235 total delegates, more than half the number needed to clinch the nomination when the count includes superdelegates, who are elected officials and party leaders free to support the candidate of their choice. Sanders has 580 when the count includes superdelegates