A bomb has exploded in Seaside Park in New Jersey before planned 5km race, a prosecutor and local media said Saturday. The authorities in New Jersey are evacuation about 30 homes near the site of explosion.

An improvised explosive device exploded on Saturday morning in Seaside Park, New Jersey, along the route of a major charity race that was expected to involve some 5,000 athletes, according to the local prosecutor's office.

"An explosive device discharged within a garbage pail… at approximately 9:35 am [13:35 GMT]. There are no reported injuries or damage to surrounding structures. The Ocean County Prosecutors Office Arson Unit is on scene and will be assisted by FBI, ATF and NJ State Police Bomb Squad," the office said in a statement.

A Semper Five race, that was expected to have started by then, was delayed due to late sign-ins, "which thankfully avoided a large number of runners in the area", the statement read.

Another device was reportedly found nearby later in the day after police put the area on lock down and began search operations, according to the prosecutor's office spokesman.

BREAKING: IED explodes, another found on route of Marine Corps race in New Jersey https://t.co/fMUHJJj1bN pic.twitter.com/uZmUCiiE5s — Justin Miller (@justinjm1) 17 сентября 2016 г.

State police, Federal Bureau of Investigation (FBI) and the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) searched the area while local authorities evacuated some 30 houses near the site of the explosion, reports said, quoting the Ocean County Sheriff's Office.

US security forces have stepped security at sports events after the 2013 Boston Marathon bombing that killed three people and injured more than 260. In early 2016, the FBI sent over 200 agents while police deployed some 5,000 officers to monitor April's Boston Marathon with the operation also incorporating lessons learned from the terrorist attacks in San Bernardino and in Europe.