Police early Monday said a search of two terminals at Kennedy Airport showed no evidence of gunfire reported earlier that forced the evacuation of the buildings.

A tweet from the NYPD Special Operations unit said officers had swept both terminals and found “negative results.”

Terminals 1 and 8 remained closed just before 1 a.m. Monday but both were expected to resume operations soon, police said.

The NYPD tweet followed a statement by Port Authority police late Sunday night saying that “a preliminary investigation does not indicate shots were fired at JFK.”

The statement said there had been no initial evidence to confirm the gunfire report.

“There are no injuries,” the Port Authority police said. “At this time, no firearm, rounds or shell casings or other evidence of shots fired has been found. To be cautious, the terminal was evacuated. Travelers should contact their carriers.”

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Late Sunday night, both terminals were evacuated, forcing passengers from the buildings and delaying flights amid the crush of the mid-August vacation season after authorities received the reports of gunfire.

After the first report at 9:30 p.m. of shots fired inside Terminal 8, Port Authority police evacuated the building.

About 45 minutes later, a second report of gunfire came in, this time from Terminal 1, officials said, leading police to evacuate that building and shut it down.

Port Authority police and NYPD officers moved in and combed both terminals in search of anyone with a weapon.

Airline officials said the evacuation came just as they were dealing with flight delays because of multiple weather problems across the country. Multiple carriers had stopped arrivals and departures but it was unknown early Monday how long flights would remain grounded.

Outside the closed terminals, passengers crowded the sidewalks bordering the airport’s arrival and departure lanes.

Traffic in an out of the airport came to a stop as police officers were pressed to get vehicles in an out while passengers wandered nearby.

Numerous emergency vehicles responded with lights flashing, adding to the tangle of private vehicles, taxicabs, livery vans, and baffled or rattled passengers. The standstill was not limited to the airport. Authorities diverted traffic off the nearby Van Wyck Expressway and onto surface streets. The expressway serves as a major route for traffic to and from the airport.

Inside the parts of the airport not evacuated, the business of travel went on with travelers staring up at flight monitors, grabbing their luggage, or registering at airline desks.

But inside the terminals that would soon be closed, the scene was anything but calm, according to several television news reports.

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Travelers said word spread quickly through the terminals about the possible gunfire. Many customers — some toting suitcases and other personal items — ran from the terminals and into the warm, muggy night long before police emptied the buildings.

Other passengers said they were evacuated and left stranded on one of the airport’s tarmacs outside as they waited for information about the situation inside the terminals. Some passengers spoke by phone on planes parked on the tarmac, unable to either push toward an assigned gate or be cleared to take off.

Officials said they had no information about the source of the gunfire reports and the investigation was expected to continue well into Monday.

“Police received reports of shots fired at Terminal 8 at JFK at about 9:30,” said Joseph Pentangelo, a police spokesman for the Port Authority of New York and New Jersey, which operates the airport. “This apparently was near the departures area.”

He added that there were no injuries reported despite the evacuations and heightened anxiety.

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“We have no actual confirmation of shots fired,” he said.

Pentangelo said after the second report of gunfire, Terminal 1 officials closed the building as a precaution.

American Airlines spokeswoman Victoria Lupica could not say late Sunday night how many of the carrier’s flights were delayed. She said the airline had already been dealing with weather-related flight delays.

“We have an ongoing security situation at JFK,” Lupica said, adding that there were no injuries to employees or passengers and the ticket counter had been closed. “We will provide more details as they become available.”

With Scott Eidler