The NYPD said Monday that no arrests have been made after three so-called “mole people” emerged from a manhole just steps from Penn Station’s main entrance last week, a bizarre scene that rattled passersby in one of Manhattan’s busiest corridors.

“I just immediately thought, reconnaissance, 9/11,” said an Arizona tourist named Mark to The Post in packed Herald Square in Manhattan.

“If you’re an Iranian soldier, you need to cripple New York City? Under Penn Station? Under Madison Square Garden? Aren’t all the train lines crisscrossing here?”

The unusual incident unfolded around 4:20 a.m. Aug. 18, when video captured three people in headlamps and overalls climbing out of a sanitation and drainage manhole about 150 feet from Penn Station and just one block from Madison Square Garden before quickly walking away.

A worker connected to nearby Penn 2 developer Vornado Realty Trust said he knew police had been canvassing the crowded commercial and tourist area, seeking possible surveillance footage that might show the late-night trespassers.

“The more they told me about it, the more I wanted to get transferred to another area,” the man said.

The Penn Station episode echoes two earlier “mole people” sightings in Brooklyn this year, cases that resulted in several arrests of individuals police believed were searching underground for valuables.

Law-enforcement sources said investigators have gathered surveillance video that may have recorded the latest incident and are working to identify the three people, potentially using facial recognition technology, in an effort to determine why they were there.

“The NYPD is aware of the incident and is actively investigating,” the Police Department said in a statement to The Post on Monday.

“There are no arrests and the investigation is ongoing.The incident occurred on August 18, 2026 at 0419 hours at the southeast corner of West 31st Street and 7th Avenue.”

A law-enforcement source said, “There is nothing to indicate there is any criminal activity here besides trespassing.

“The manhole covers lead to the sewer system. But who knows what someone is doing down there if they are looking to cause [trouble].”

Another source called the situation “not uncommon.

“Mostly people who do this think there’s treasure. Precious metals. Lost property.

“Yes, [the sewer-hunting is] not ideal from a security standpoint. But it’s [the city Department of Environmental Protection’s] infrastructure to secure,” the source added.

A rep for the DEP, which has domain over the thousands of miles of sewers and drainage system under the Big Apple, was asked Monday by The Post about the incident but only referred to its statement Sunday, sayin an inspection of the sewers revealed no damage to the infrastructure.

“Members of the public should never enter a pipe, drain, catch basin, manhole or outfall,” it said.

Law-enforcement sources said the latest “mole people” pop-up could be similar to the Brooklyn ones.

In those cases, several people were caught on camera disappearing and jumping out of manholes in Williamsburg and Gravesend in separate incidents in May, sparking an NYPD probe.

At least four people were charged with trespassing in those incidents, with law-enforcement sources telling The Post they were looking for valuables.

Other sources suggested the Manhattan incident might be part of a scheme for TikTok footage, given it was caught on film so early in the morning.

“It could be anything,” said Ari, a fashion worker in the Manhattan neighborhood. “Kind of sketchy the way they’re running away after they come out of the hole.”