A group of men shocked onlookers as they emerged from a manhole in a busy New York street in an incident that sparked a police probe.

Seven people were seen climbing out of the sewer system on Brooklyn's McDonald Avenue in Gravesend.

The dramatic exit was caught on camera as it occurred at around 2am on Friday and was published by local outlet Flatbush Scoop.

The men began stripping off their filthy clothes after they got out of the hole and then gathered near waiting cars.

Some appeared to be carrying equipment and flashlights, while others seemed to be wearing boots and protective gear. 

Video circulating online appeared to show a person remaining near the manhole while the cover stayed closed, seemingly acting as a lookout. 

The bizarre sight prompted the New York City Police Department (NYPD) to visit the scene several hours later. 

They said investigators have been unable to determine how long the group spent inside the sewer network or why they entered it in the first place.

Footage from the investigation showed an NYPD officer wearing a respirator mask and stained protective coveralls being assisted out of the manhole after apparently searching sections of the sewer below.

Additional reports suggest the men may have been underground for close to two hours before resurfacing. 

The incident appears to be one of several similar instances across the borough, with witnesses reporting another group descending into a manhole in Williamsburg at Bedford Avenue and Lynch Street.

Portions of the area around McDonald Avenue between Kings Highway and Avenue S were shut down while officials worked to determine whether there were any hazards underground.

Crews from the city's Department of Environmental Protection also arrived at the location to conduct their own inspection of the infrastructure below the street.

A spokesperson for the department said workers were 'inspecting the sewer infrastructure at this location to ensure there is no damage to the system.'

The agency also issued a stark warning about the dangers associated with entering the city's sewer network.

'Entering the sewer system is both illegal and extremely dangerous,' the spokesperson said in a statement.

'Sewers can contain numerous hazards, including noxious and potentially deadly gases, unstable surfaces, flooding risks, and confined spaces.'

Despite the dramatic scene and hours of investigation, police said no arrests had been made as of Friday evening.

The NYPD's 62nd Precinct later attempted to reassure residents, posting on social media that the location had been examined and was considered safe.

According to the department, the area was found to be 'safe and free of hazards.'

Both incidents occurred in predominantly Jewish neighborhoods of Brooklyn. 

In 2024, illegally-dug tunnels were discovered being used by young Orthodox Jewish men in an attempt to link a synagogue to a nearby ritual bath at the Chabad Lubavitch global headquarters in Crown Heights.

Members of the Hasidic Jewish community were arrested and charged over a 60ft secret tunnel.

The leaders of the synagogue only discovered the tunnel after neighbors complained of hearing people speaking Yiddish under their floors.