The Center City offices of the Defender Association of Philadelphia were evacuated for about two hours Monday morning after a man threatened to blow up the building, Philadelphia police said.

About 10 police cruisers were parked outside the office building on the 1400 block of Sansom Street as officers from the K-9 unit searched inside. The street was closed to vehicular traffic and more than a dozen employees were waiting across the street near the Union League of Philadelphia.

Police said that officers responded to the scene around 9 a.m. due to reports of a man threatening to blow up the building, but they did not say who made the threat or how, or whether anyone had been taken into custody.

Employees were allowed back inside the building just before 11 a.m. The Defender Association provides legal services for indigent defendants.