Transport for London (TfL) said it had received a report of a stray dog that had jumped off the London Bridge.
The dog, described as white with a black head, was last seen on Sunday afternoon and the owner reported it to police, TfL said in a statement.
TfC’s Dog Response Team is currently at the scene and will take a closer look into the dog, who is believed to be between two and four years old.
It is believed the dog jumped from the southbound carriage of the bridge, which was closed for three days on Monday.
Tfl said it would assist the dog owner with finding the owner and bringing it to the scene, where it would be put down.
The animal is described as having white, medium length hair and a thin build.