How to import a .pub file into PGP Command Line

I have recieved a .pub file from the customer having his public key. Now i need to encrypt the files using this public key but for this i need to import this key into my PGP rings.

With a .asc file i can easily import the public key using the import command

pgp --import "filename.asc"

but when i try to import the .pub file using the same way it throws me error.

I also tried changing the extension from .pub to .asc the key was imported but i cant encrypt the files using that key.

Can anyone of you help me in this what is the correct way to import .pub file into PGP Command Line