WATCH LIVE COVERAGE: New York presidential primary election results

New Yorkers voted Tuesday in the state's most decisive presidential primary in decades with Hillary Clinton and Donald Trump strong favorites in the race to clinch the Democratic and Republican nominations.

RELATED: No, votes were not changing from Hillary to Bernie on electronic voting machines in NY

Watch live coverage starting at 6 p.m. ET, courtesy of ABC News, below. (Polls close at 9 p.m.)

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The Young Turks' coverage of the primary is also streaming live, and can be seen here.

Polls show that Clinton -- the former secretary of state, first lady and New York senator -- has a double-digit lead over her Brooklyn-born challenger, Bernie Sanders, even if nationwide surveys put them neck-and-neck.

Trump, the 69-year-old Manhattan billionaire whose controversial campaign has appalled the Republican establishment, is well ahead of his evangelical rival Ted Cruz and Ohio Governor John Kasich.

The tycoon is banking on a big home state victory in his quest to sew up the nomination before Republican grandees can anoint another candidate at the party convention in July.

"It was just a great honor and I think it's a great honor for New York," Trump said after voting in a synagogue, reiterating his campaign slogan. "We're going to make America great again."

A relaxed and confident-looking Clinton, 68, dressed in a colorful tunic, voted with her husband, former president Bill Clinton, in the leafy Chappaqua suburb they call home, taking time to greet well wishers outside.

"I had a great time going around the city in the last couple of days just seeing a lot of old friends, meeting new people," she said. "Everybody please come out and vote before 9:00 pm tonight. That would be terrific."

With both races for the White House nomination so competitive, it is the most consequential primary in decades in New York, the country's fourth largest state and one with a vastly diverse electorate.

Three of the candidates lay claim to calling New York home: Trump, who has never lived anywhere else; Clinton, who was twice elected the state's US senator; and Sanders, who was raised in Brooklyn but is now a US senator from Vermont.

In a disadvantage to Sanders, independents are barred from participating. Only New York's 5.8 million Democrats and 2.7 million Republicans who registered by last October are eligible to vote.

Turnout was steady at polling stations visited by AFP in Manhattan and Brooklyn, where a string of Democrats said they had voted for Clinton, who would make history if elected as America's first woman president.

- Hillary knows how -

"I think she's got the record across all of the issues that matter to me," said Rachel Karpf, 30, an arts producer who works in theater and lives in Brooklyn.

"I like Bernie Sanders, I love his energy and his passion," said Carlos Rios, a human resources manager in Chelsea.

"But I worry that he is not going to be able to withstand the political reality we have today, and for better or worse, Hillary knows how to navigate."

A victory in New York, which also selected Clinton over Barack Obama in 2008, would quash the momentum generated by her self-styled democratic socialist rival, who has won seven out of the last eight state nominating contests.

Only California has more than the 247 Democratic delegates and 44 superdelegates up for grabs in New York on Tuesday.

Clinton already leads with 1,791 compared to 1,115 for Sanders, according to a CNN tally -- putting her on course to clinch the 2,383 delegates needed to secure the party's presidential nomination.

The 74-year-old Sanders -- who has galvanized a youth movement with his call for health care as a right, free college education and campaign finance reform -- needs a win to keep alive his hopes of winning the presidency.

But in stark contrast to victory parties arranged by the Clinton and Trump campaigns in New York, Sanders has opted to spend Tuesday in the neighboring state of Pennsylvania, which holds its primary next week.

The senator has also signaled he could be willing to swing behind Clinton should she win the nomination, provided she moves further to the left on causes that he has highlighted.

"It's a two-way street," he said. "The Clinton people are going to have to say, 'You know, maybe Bernie has a point,'" he told CNN on Monday.

While New York City is largely Democrat, Republicans in rural areas and fallen manufacturing cities upstate have warmed to Trump's populist message despite his insults of women, Mexicans and Muslims.

The tycoon led the New York polls 53.1 percent, with Kasich and Cruz languishing at 22.8 and 18.1 percent, respectively, according to RealClearPolitics.