Presidential candidates Hillary Clinton and Donald Trump have spoken out in the wake of an explosion in New York City which left 29 people hurt.

Both Clinton and Trump are referring to the explosion in New York City as a bombing, a description authorities didn't use publicly in the early hours of the investigation.

Trump, the Republican nominee, had just arrived in Colorado Springs, Colorado, for a rally Saturday night when he said 'a bomb' had gone off in New York City and that 'nobody knows what's going on'.

Scroll down for video

Trump, the Republican nominee, had just arrived in Colorado Springs for a rally Saturday night when he said 'a bomb' had gone off in New York City and that 'nobody knows what's going on'

He was filmed saying at the event: 'I must tell you that just before I got off the plane, a bomb went off in New York and nobody knows exactly what's going on.

'But boy, we are living in a time - we better get very tough folks, we better get very, very tough.

'Just happened, so we'll find out, but it's a terrible thing that's going on in our world and in our country and we are going to get tough and smart and vigilant and we're gonna end it. We're gonna end it.'

Clinton, the Democratic nominee, said she has been briefed about explosions in New York and New Jersey and a mall attack in Minnesota and is calling on the nation to support first responders and to pray for victims.

Clinton told reporters traveling with her: 'Obviously we need to do everything we can to support our first responders - also, to pray for the victims'

She told reporters traveling with her: 'I've been briefed about the bombings in New York and New Jersey, the attack in Minnesota. Obviously we need to do everything we can to support our first responders - also, to pray for the victims.

'We have to let this investigation unfold. We've been in touch with various officials including the mayor's office in New York to learn what they are discovering as they conduct this investigation.

'And I'll have more to say about when we actually know some facts.'

The blast in Manhattan's Chelsea neighborhood is thought to have come from a dumpster (pictured) and could have come from an explosive device. Witness Chris Duffy tweeted this photo of a destroyed dumpster and said it was the source of the blast

Police in New York City are investigating an explosion that injured twenty-nine people.

In New Jersey, a pipe bomb exploded in Seaside Park shortly before a 5k run but caused no injuries.

At least eight people were taken to a hospital with injuries after a stabbing attack at a St. Cloud, Minnesota, shopping mall on Saturday evening which ended with the suspected attacker dead inside the mall.