Republican Donald Trump and Democrat Hillary Clinton scored sweeping victories in nominating contests in their home state of New York, and immediately cited them in arguing they are all but unstoppable as their respective parties' presidential nominees.

Trump's crushing defeat of Ted Cruz in Tuesday's primary election tilted the energy in the Republican race back to the front-runner, just as Republican National Committee members begin meeting in Florida on Wednesday to discuss their July convention, where the nominee will be chosen.

For the Democratic favorite, Clinton's more narrow victory over Bernie Sanders snapped a string of victories by the 74-year-old democratic socialist and gave her a much-needed lift with more tough fights ahead.