A shooting yesterday outside a restaurant in central Buffalo, New York state, left four people dead and three injured, police said.

The restaurant held a wedding reception earlier in the night, but police didn't know if anyone in the wedding party was involved, police chief Dennis Richards said.

Officers responding to a report of a shooting at City Grill, a bar in the city's business district, at about 2.30am found three people dead, he said. A fourth died in hospital.

"We're checking to see if something precipitated this from inside," Richards said.

He said the dead were three men and one woman. Their identities hadn't been released. The other victims were taken to hospital.

Richards said one victim was in a serious condition.