The rusted metal aircraft part believed to be from one of the hijacked jetliners that slammed into the World Trade Center in the Sept. 11, 2001 terror attacks came from a wing, not landing gear, police said Monday.

The 5-foot (1.5-meter) piece is a trailing edge flap support structure, police said. It is located closer to the body of the plane and helps secure wing flaps that move in and out and aid in regulating plane speed. Investigators initially thought it was part of the landing gear because both pieces have similar-looking hydraulics.

Boeing officials told police the part came from one of its 767 airliners, but it isn't possible to determine which flight. Both hijacked planes that struck the towers, American Airlines Flight 11 and United Airlines Flight 175, were Boeing 767s. American and United had no comment.

Workers discovered the part Wednesday on the ground in a sliver of space between a luxury loft rental building and a mosque that in 2010 prompted virulent national debate about Islam and freedom of speech in part because it's near the trade center site. Other World Trade Center wreckage has been discovered at the buildings and around the area in years past.

An inspector on the roof of the mosque site, which is under construction, noticed the debris and then called police.

Police documented the debris with photos. The twisted metal part _ jammed in an 18-inch (45-centimeter)-wide, trash-laden passageway between the buildings _ has cables and levers on it and is about 5 feet (1.5 meters)high, 17 inches (43 centimeters) wide and 4 feet (1.2 meters) long.

There's no indication that the part was planted in the space, said Paul Browne, chief spokesman for the New York Police Department.

Of the nearly 3,000 victims of the trade center attacks, remains of about 1,000 were never recovered, and sifting the site for possible human remains was to begin Tuesday morning, said the chief medical examiner's spokeswoman, Ellen Borakove.

Police said the part would be moved to a more secure location likely later this week, where a determination will be made about where it will go permanently. In the past, such pieces have been treated as historical artifacts. For example, the New York State Museum in Albany has in its collection a large landing gear piece that fell through the roof to the basement at the same location. It was placed there in 2002.

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Associated Press writer Jennifer Peltz contributed to this report.