Four Chinese nationals, all women, were among the 14 people killed on Friday by a lone gunman at an immigration services center in upstate New York, local police have said.

The victims' identities were being established and would be released as soon as possible, according to the police, who notified the Chinese Consulate-General in New York of the deaths.

The victims, who were from different families and had diverse backgrounds, attended the same class at the American Civic Association (ACA) - a non-governmental agency that provides services for immigrants and refugees - Deputy Consul General Shi Yong said.