Two workers died after they became trapped under construction rubble at John F. Kennedy International Airport on Monday, authorities said. 

The workers were relocating utility lines inside a trench at the airport just after 11 a.m. when they were caught under rubble, the FDNY and the Port Authority of New York and New Jersey said. 

Emergency responders pronounced both workers dead at the scene, the FDNY said. Authorities didn’t immediately release their names or ages. 

A stop work order was issued at the site after the incident, the Port Authority said. The utility line work was being carried out as part of an ongoing redevelopment project at the airport, the agency said. 

“The Port Authority is conducting a thorough investigation and will be cooperating with all other investigative agencies,” the agency added.