Cops responded to a shots fired call after 11 PM Tuesday night and found the rapper's bus had been shot up outside the hotel where he's staying. Police checked the bus and discovered nobody was on it, and no one had been hit in the hail of gunfire.

Bullet holes peppered the bus, and at least one tire was blown out. It's unclear if the motive was simply to vandalize the bus or worse ... cops are investigating, but no arrests so far.

Gotti had just performed earlier in the night at the Mercy Lounge. It's unclear if he'd ridden the bus back to his hotel room prior to the shooting. A witness tells us he heard rapid gunfire for about 6 seconds and then heard screeching tires as a car sped away.