Center City traffic was snarled for about an hour Thursday afternoon while police and the FBI investigated a bank robbery and bomb threat inside a PNC Bank branch on Market Street between 11th and 12th.

Authorities said a man walked into the branch next door to the Pennsylvania Convention Center and announced a robbery just after 3 p.m., saying he had a bomb inside a bag. The man then left the bag inside the bank and fled. It was unclear how much money, if any, he took.

The building and part of the block were evacuated immediately after the incident as the bomb squad was called in to investigate.

Around 4 p.m., officials determined that the bag did not contain a bomb, but rather a bottle of water, and the scene was cleared and Market Street reopened to foot and auto traffic. There were no reported injuries.