New York police investigate videos of men emerging from city's sewer system

New York police are investigating after multiple videos emerged in recent weeks showing groups of people entering and climbing out of the city's sewer system.

The men, captured on surveillance cameras in neighbourhoods across Brooklyn and Queens, are believed to be searching for valuables underground, US media reported citing police sources.

It remains unclear whether the same group is behind all the incidents. In one video, several men are seen removing a manhole cover and then descending into the sewer before re-emerging hours later.

"Entering the sewer system is both illegal and extremely dangerous," a spokesperson for the city's Department of Environmental Protection (DEP) told the BBC.

"Sewers can contain numerous hazards, including noxious and potentially deadly gases, unstable surfaces, flooding risks, and confined spaces," the DEP spokesperson said. "For these reasons, members of the public should never enter a pipe, drain, catch basin, manhole, or outfall."

Last week, police received reports of several unidentified individuals removing manhole covers and entering the sewer system.

"The individuals then fled the location in an unknown vehicle to parts unknown," the New York Police Department told the BBC. "There were no injuries reported. There are no arrests, and the investigation remains ongoing."

The men who were caught on video climbing out of a sewer manhole are believed to be "treasure hunters" and urban explorers looking for valuables in the sewer system, police sources told CBS News, the BBC's US partner.