Police are looking for gunmen who shot up a party bus in Santa Monica, killing a woman passenger.

Police say two unrelated party buses were parked near the Santa Monica Pier at around 1 a.m. Saturday when a group from one bus got into an argument with a group from the other bus.

Police say two or three men opened fire on the other bus, hitting several people inside, then ran off.

The driver drove the bus to the police station.

One person was treated at the scene for minor injuries and three others were taken to a hospital, where a woman in her 30s died and the other two victims are in stable condition.

No arrests have been made but police say four guns were found.