At least 29 people have been injured in an explosion in New York.

Police say the explosion was intentional, but that there's no evidence of terrorism at this point.

The blast happened on West 23rd Street between 6th and 7th Avenues, a fashionable thoroughfare in downtown Chelsea, at around 1.30 am Irish time.

Police searching the area around the scene have also found a second device.

The city's Mayor Bill de Blasio has urged all New Yorkers to remain calm: