New York police says FBI terror unit joins probe into blast in Long Island

The FBI has joined New York law enforcement in looking into a sonic blast that left a crater on a Long Island beach and was reportedly felt miles away.

The Suffolk County Police Department said the explosion Sunday occurred on an uninhabited island off the coast of West Babylon, at about 11:40 a.m. Authorities received nearly three dozen 911 calls, the department told Fox News. 

Authorities are reportedly concerns that the incident could be terror related and a prelude to a more large-scale incident.

"Terrorism is always a concern because people do test devices before using them," a police spokeswoman told Fox News. "The SCPD is investigating with the FBI Joint Terrorism Task Force on this investigation."

The blast left a roughly 4-foot wide, 2-foot deep crater in the sand, and a boat was reportedly seen in waters near the island near the time the explosion occurred.