investigation into a blast in Seaside Park that occurred shortly before thousands of runners were due to participate in a charity 5K race to benefit Marines and sailors.

Brad Cohen, the acting special agent in charge of the FBI’s office in Newark, declined to discuss the matter at length during a brief news conference staged Saturday evening.

He said the FBI is working side by side with federal, state and local officials to find out who is behind the device.

“We’re out there conducting interviews, we’re out there securing evidence and we’re making sure that there is no stone left unturned,” Cohen said at a news conference Saturday evening.

But officials won’t say whether they believe the incident was terror related. Cohen declined to take questions from reporters, citing the “active, ongoing” investigation.

No injuries were reported in the blast, which happened around 9:30 a.m. Saturday, when a device exploded inside a plastic garbage can at the corner of D Street and Ocean Avenue, authorities said.