Rescue workers arrive at Central Park in New York, the United States, on July 3, 2016. An explosion happened early on Sunday at New York's Central Park, leaving one man seriously injured. [Photo/Xinhua]

NEW YORK - The explosives that severely injured a young man Sunday in New York's Central Park was likely an "experiment with fireworks or explosives," authorities said.

Commanding Officer of the NYPD Bomb Squad Mark Torre told a press conference that the Fourth of July holiday was a typical time of the year that the squad dealt with a lot of homemade explosives experimentations.

Torre said the squad had not found anything consistent with a constructed IED in the explosion, adding that the explosives could be made by somebody with a knowledge with chemistry.

"There's nothing to indicate that this was an explosive device that was placed in this area with a specific intend to harm any individuals," said Torre.

"At this time, we have no evidence that this is related to terrorism," said NYPD Deputy Chief John O'Connell.

"There're no specific credible threat directed at New York or the July Fourth celebrations," O' Connell added.

O'Connell said the police did not consider the victim and his two friends were part of the construction of the explosives.

The blast occurred when the 18-year-old man stepped on the explosives on a rock structure in the renowned Central Park, seriously injuring his left foot.

According to the police, the victim was undergoing surgery and his condition was stable.

Officials said the police were checking the park for any more explosives by looking through video surveillance camera footage, sending many police detectives and bomb-sniffing dogs, including some specially trained vapor wake detection dogs.

The investigation was still underway.