Two men were fatally shot Tuesday afternoon at Navy Pier by a gunman who authorities believe was a recently terminated worker.

Speaking with reporters at the pier, Chicago police Chief of Patrol Jon Hein stressed that authorities did not believe the suspect posed a danger to the public, though the shooter remained at large as of 4:30 p.m. Tuesday.

“This was an isolated incident with a disgruntled ex-employee,” Hein said.

The gunman, thought to have been terminated Oct. 14, had sought out two employees around 1:20 p.m. in a loading dock and nearby administrative office at the far end of the pier and fired multiple shots.

The two men were taken to Northwestern Memorial Hospital, where they died. Their identities weren’t immediately released.

Hein offered few details about the investigation into the slayings, saying only that authorities were “actively seeking” a person of interest.

Navy Pier’s Chief Operations Officer Brian Murphy said the facility went on lockdown and notified all tenants of the building of the shooting.

“Once we were able to determine that the offender had left the property, we were able to open back up,” he said.

Hours after the shooting, red crime-scene tape blocked the entry to the loading dock at the far end of the pier and one officer advised another “be careful of that blood” as she left the entryway.

Cars exited the parking lots alongside the north end of the pier as construction workers were milling around a crane at the pier’s far end. A commander directed the news media to move away from the crime scene.

People were coming and going from the pier’s main hall even as police still clustered at the entrance.

Navy Pier is considered one of the city’s main tourist attractions downtown, drawing nearly 9 million visitors annually, according to the venue’s website.

Philadelphia visitors Bob and Bobbi Ann Kane, who were staying at the pier’s Sable Hotel, were upbeat as they strolled the pier Tuesday afternoon, despite the startling nature of the shooting.

At the time of the shooting, Bob Kane, 62, was visiting McCormick Place, while Bobbi Ann, 61, who had just stepped out of their hotel room, realized businesses were closing unexpectedly. Then she saw SWAT officers walking past her and heard a shelter-in-place order, prompting a call to her husband.

“I was worried,” Bob Kane said. “I couldn’t get here (quickly) enough. So I didn’t know what to do. Then when I got here, I couldn’t get in.” The couple was reunited after the roughly two-hour lockdown.

Another out-of-town visitor, Trent Halasek, of Cincinnati, said he was wandering through the pier’s sprawling structure and made a quick stop at the Ferris wheel before exiting to find police.

“Then two of the police officers got out of the car, ran to the back,” he said. “Then I was like, ‘What on earth is going on?'” More cars pulled up and he saw officers in SWAT gear entering the building.

After a few minutes of panic, Halasek said the situation calmed. “It’s a bit surreal,” he said. “You never think you’re going to be somewhere where that happens.”