Donald Trump moves closer to GOP nomination after winning Indiana primary

Republican front-runner Donald Trump scored an important victory over rival Ted Cruz in Indiana on Tuesday, a win that moves him close to being unstoppable in his march to the party's presidential nomination.

The New York billionaire was quickly projected to be the winner by television networks shortly after polling places closed in the Midwestern state. Trump was on track to take well over 50 percent of the vote, eclipsing Cruz, a U.S. senator from Texas. Ohio Governor John Kasich was running a distant third.

On the Democratic side, Hillary Clinton was well ahead over Bernie Sanders as votes continued to be counted.

Cruz had been counting on a win in Tuesday's primary to slow the New York businessman's progress toward the nomination. But polls in recent days showed Trump opening up a substantial lead in the Midwestern state over the senator, whose brand of Christian conservatism had been expected to have wide appeal in the state.

Campaigning in Evansville, in the state's southwest corner, Cruz sounded deeply frustrated by the bombastic real estate mogul, who has ripped Cruz at every turn.

"The man cannot tell the truth but he combines it with being a narcissist," Cruz said, "a narcissist at a level I don't think this country has ever seen."

Cruz's fury was triggered when Trump said in a television appearance that the senator's father, Cuban emigre Rafael Cruz, was linked to John F. Kennedy's assassin, Lee Harvey Oswald. Trump was referring to a report by the National Enquirer, a supermarket tabloid known for celebrity gossip and alien sightings.

Cruz termed Trump a "serial philanderer" - likely as part of his strategy to try to win the support of evangelical voters. Trump, in response, said Cruz had become "more and more unhinged."

(Reporting by Ginger Gibson and Alana Wise; Additional reporting by Emily Stephenson and Megan Casella in Washington; Writing by Steve Holland; Editing by Alistair Bell, Andrew Hay and Leslie Adler)