A part from one of the commercial planes that was flown into the Twin Towers on 9/11 has been found between two buildings, police say.
New York Police Department Spokesman Paul Browne said the piece of landing gear, discovered on Wednesday wedged between a mosque site and another lower Manhattan building, has a clearly legible Boeing identification number.
The twisted and rusted equipment features cables, levers and giant bolts. It measures 5ft high, 3ft wide and 1.5ft deep.
"The odds of this being wedged between there is amazing. It had to have fallen just the right way to make it into that space," Browne said.
He added that other wreckage has been found nearby in the years since the terrorist attack.
The part was found by surveyors who had been hired to inspect the site of a planned Islamic community centre at 51 Park Place, about three blocks from ground zero.
The surveyors spotted the debris as they looked down between the buildings from the roof, quickly called 911, and the scene was secured and police documented the findings with photographs, Mr Browne said.
The National Transportation Safety Board and police will work to determine whether the wreckage belongs to American Airlines Flight 11, which struck the North Tower, or to United Airlines Flight 175, which crashed into the South Tower. Both planes were Boeings.
Police are awaiting a determination from a medical examiner on whether to sift the soil around the building to search for human remains.
The medical examiner's office is in the middle of a 10-week sifting operation as it attempts to identify additional human remains in debris unearthed at the World Trade Center site during construction of a new skyscraper.
If the landing gear's origin is authenticated, it would mean it sat undisturbed for nearly a dozen years.
Patricia Riley, the sister of 9/11 victim Lorraine Riley, called the discovery "very strange."
"Twelve years later we are still finding remnants of the attack on our country," she said.
"For years to come we'll continue to find things that we didn't see before. Hopefully, they'll serve as a reminder that we have to stay vigilant."
More than 2,750 people were killed at the World Trade Center on September 11, 2001, when terrorists hijacked the two commercial passenger planes and flew them into the upper floors of the Twin Towers, then the tallest buildings in the world.
Hijackers also took over two other planes that day, crashing one into the Pentagon in Washington DC.
The fourth plane went down in a field in rural Pennsylvania.