Electric Boat employees were evacuated from their workspaces after a bomb threat was made Tuesday morning against two submarines undergoing maintenance at the company’s Groton shipyard.

"Out of an abundance of caution for the safety of our workforce and our Navy teammates and consistent with our security protocols, we safely evacuated all personnel from the impacted area so that EB Security, along with state and federal officials could complete an appropriate search and investigation," Liz Power, company spokeswoman, said in an email Tuesday afternoon.

Power did not specify the number of employees who were evacuated. By mid-day, law enforcement officials had completed their search and employees had returned to their workspaces, she said. An investigation is ongoing.

Jeff Houston, a spokesman with the Naval Criminal Investigative Service confirmed in a statement late Tuesday afternoon that NCIS had responded to "a report of a written bomb threat involving two submarines currently docked at Electric Boat for repairs."

"NCIS is working closely with the commands, Electric Boat, the FBI, and the Connecticut State Police to conduct initial investigative steps. Out of respect for the investigative process, NCIS will not comment further," Houston said.

Anyone with information about the threat is asked to report it to the NCIS Tips app or https://www.ncis.navy.mil. Tips may be reported anonymously.