Andre Berto -- Mayweather's a Telephone Terrorist ... Stop Harassing Me!!!

Floyd Mayweather has been waging a telephone war on Andre Berto -- making harassing and annoying calls to the boxer ... and it's all over a woman, this according to Berto.

Berto appeared on "TMZ Hollywood Sports" on Wednesday and told us that he respects Floyd as a fighter -- but he's sick of all the drama that's been going on outside the ring.

FYI -- Mayweather recently said he's considering Berto as his next opponent ... though the two have not signed a deal yet.

But Berto says he's more frustrated with the wave of harassing phone calls he's received lately ... and he's convinced Mayweather is the one behind the telephonic hostility.

"I know it's him on the other line. I can hear him breathing."

So, why would Floyd do it? Berto suggested Floyd is upset with him over an issue involving a woman.

Sources connected to the situation tell us ... Mayweather is upset that Berto is friendly with his ex-fiancee Shantel Jackson and her new boyfriend Nelly.