An explosion along the route of a Marines charity run in New Jersey Saturday morning prompted a lockdown, as authorities canvassed the area for other possible explosive devices.
Nobody was injured in the incident because of an unexpected delay, but thousands were expected to take part in the race.
The FBI's Joint Terrorism Task Force unit will be leading the investigation into the explosion, Brad Cohen, acting special agent in charge of the FBI's Newark office, said at a press conference.
"We are working side by side with our law enforcement partners — federal, state, and local — and we're working together to conduct a thorough investigation to find out who is responsible," Cohen said.
There was no known threat to the community, Cohen said.
The explosion occurred around 9:30 a.m. in Seaside Park in New Jersey, officials said.
The Seaside Semper Five, a 5k Marine Corps charity race, had been scheduled to begin at 9 a.m., but was delayed by 30 minutes.
"Because of that delay there probably would have been a good number of people running past that trash can when it went off," Ocean County Prosecutor’s spokesperson Al Della Fave told News 12 in an interview aired on CNN.
"It’s obvious that this was meant to affect the run,” he said.
Della Fave said preliminary investigators had described the device as a "pipe bomb–type device."
"Initial reports of a second device found in another trash can have been refuted," New Jersey State Police said in their statement. "However, State Police bomb technicians have rendered safe items located in the same trash can in which the explosion occurred."
The charity organizers canceled the event, and law enforcement placed the immediate area of Seaside Park on lockdown.
The FBI and the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) joined local police in the investigation, state police said.
"We are taking every step to ensure the safety of the public and to determine who was responsible for this explosion, which occurred at a time when runners in this charity race could have been in harm's way,” Attorney General Christopher Porrino said.
"We are grateful that nobody was injured, but this is a serious act of violence against the people of New Jersey. We will not rest until we find the person or persons responsible," he said.
By 5:30 p.m., FBI officials said the lockdown that had been placed in the area had been lifted, but residents who live near the area where the explosion occurred would have to show an ID to get home.
The beach, officials said, would remain off limits to the public until further notice.