Three people were injured Tuesday morning in an accident involving a mail truck.

It happened around 10 a.m. on the corner of First Avenue and 37th Street in Manhattan.

A source on scene says the driver was not paying attention while backing up. 

Authorities say the truck entered the crosswalk, striking three pedestrians.

They were all treated for minor injuries at Bellevue Hospital. 

The mailperson and postal truck remained on scene.