Manhattan's 2 World Financial Center was evacuated Thursday morning after workers who discovered what they believed to be a hand grenade contacted authorities -- it turned out to be a toy, police said.

Workers in the building were screening mail with x-ray around 11 a.m. EDT when they observed what they believed to be a hand grenade, a spokesman for the New York Police Department said. The workers contacted authorities, who sent a bomb squad and evacuated the building.

Police said about 12:30 p.m. EDT the suspicious package turned out to contain a toy grenade and allowed workers back into the building.

The package was sent to Nomura Holdings Inc. (NYSE:NMR), the Japanese bank that has its U.S. headquarters in the building, said a person familiar with the matter.

Brookfield Office Properties Inc. (NYSE: BPO) owns the 44-story domed tower, which is part of a complex of four buildings to the immediate west of the World Trade Center site.

Other tenants in 2 World Financial Center include the accounting firm Deloitte LLP and Bank of America Corp.'s (NYSE: BAC) Merrill Lynch Wealth Management unit.

A spokesman for Bank of America confirmed that it has presence there and the building had been evacuated.

Representatives for Brookfield, Deloitte and Nomura couldn't be immediately reached for comment.

World Financial Center was built in the 1980s and designed by Caesar Pelli. It was damaged in the 9/11 terrorist attacks and restored afterwards.

Deloitte and Nomura signed leases last year to move out of the complex. Deloitte will take 430,000 square feet at Tishman Speyer's Rockefeller Center, while Nomura is moving to a 900,000-square-foot space at George Comfort & Sons' Worldwide Plaza.