Donald Trump has made an unfortunate blunder while campaigning on the eve of New York's high-stakes primary by getting the date of the World Trade Center attacks wrong.

During a speech in Buffalo, a slip of the tongue meant he referred to the September 11th atrocity as "7/11", which is in fact the name of a popular chain of convenience stores.

Failing to correct himself after the gaffe, the Republican front runner said: "It's very close to my heart because I was down there, and I watched our police and our firemen down at 7/11, down at the World Trade Center right after it came down, and I saw the greatest people I've ever seen in action".

The mistake could prove embarrassing for Mr Trump, as he has repeatedly mentioned the terror attacks while campaigning across New York, his home state.

Earlier this month, he also paid his first visit to the National September 11th memorial and museum.

An estimated 11,000 people were attending the rally at a hockey arena - and earlier in his speech, about a dozen protesters interrupted him by locking arms and sitting down on the stadium's floor.

Authorities carried out some of the demonstrators by their arms and legs.

Mr Trump told supporters that "no New Yorker" could vote for his rival Ted Cruz, as he did not represent what the state needs.

The businessman also expressed confidence that he would secure the 1,237 delegates required for him to become the party's presidential nominee, despite claims that he may fall short - leading to a contested convention.

In the run up to Monday night's speech Mr Trump was widely predicted to win comfortably during the contest in New York, which has 95 Republican delegates up for grabs.