State and local police with guns drawn surrounded Sovereign Bank at 1215 Chestnut St. in Emmaus around 1 p.m. Friday.
Customers at the East Penn Plaza strip mall next to the bank say they saw police shut down all four intersections there and draw weapons outside the bank until a bank employee motioned to them, apparently indicating that everything was OK.
Police then left the scene and activity at the bank returned to normal. There's no indication yet as to what prompted the response.
The same Sovereign Bank was robbed at least twice in recent years.
Police dogs and a state police helicopter were deployed for a manhunt after a July 2011 robbery.
The bank was robbed previously on July 2, 2010.