A pipe bomb exploded in a Jersey Shore town shortly before thousands of runners were due to take part in a charity 5K race to benefit marines and sailors, authorities said.
No injuries were reported in the blast in Seaside Park, which occurred around 9:30am Saturday.
But officials are now following up on reports of a second device in the area.
The pipe bomb was in a garbage can near E Street when it exploded. Authorities immediately cleared the boardwalk and beach area.
New Jersey State Police has the area on lock down while investigators track down a report of at least one other device in the area.
The race — the third annual Semper Five run — was canceled.
Officials say runners had been scheduled to pass by the area around the time the blast occurred.
But the start of the race had been delayed after an unattended backpack was found.
The FBI and the Department of Homeland Security are investigating, alongside a number of other agencies.
It wasn’t clear when the boardwalk and beach will reopen.
The 5K was organized by the MARSOC Foundation, which is a nonprofit that raises money to support active duty and medically retired Marines and Sailors, as well as their families.