NEW YORK (AP) -- A 1940s-style pineapple-shaped toy grenade was to blame for an evacuation Thursday at an office building near ground zero, and the employee responsible for bringing it inside was later placed on administrative leave.

The police bomb squad was called to 2 World Financial Center in lower Manhattan at midday when a security guard reported a mail-order package that seemed suspicious. Brookfield Properties, which runs the property, ordered an evacuation as a precaution. The building is near the World Trade Center site and was damaged on Sept. 11, when terror attacks killed nearly 3,000 people.

The gag-style gift was mounted on a plaque that said "Complaint department: Take a number," with a number attached to the grenade pin. It was addressed to someone at one of the financial institutions housed there and discovered by someone in the mail room.

A Nomura Securities spokesman said one of the company's employees was responsible for bringing the fake explosive into the building and that that person was being placed on administrative leave pending an internal review.

Employees in business suits filed calmly back into the building after the New York Police Department declared the situation all clear about 90 minutes later.

Police said there was no threat, and no criminal investigation is taking place.

The evacuated building houses major financial institutions, including Merrill Lynch, Nomura Securities, Deloitte, Commerzbank and OppenheimerFunds Inc.

Several employees said an announcement came over the building loudspeakers telling them to evacuate as quickly as possible. Octavio Diaz was wearing a neon yellow backpack as he helped lead his co-workers out of the building to a nearby volleyball court, where they waited until the all-clear.

"Stuff like this happens, so you've got to take it seriously," he said. "We're ready to go."