Washington, Dec 25 - Two volunteer firefighters, responding to a house fire in a small US town Monday were shot and killed, when someone opened fire shortly after crews arrived on the scene.

The incident occurred in a small town of Webster, in Rochester city in upstate New York.

Two other firefighters were shot and seriously wounded and an off-duty police officer received a shrapnel wound as he drove by.

After several hours the apparent shooter was found dead of a gunshot wound nearby. It was not immediately clear if the gunshot was self-inflicted or came during an exchange of gunfire with law enforcement officers.

"It appears to be a trap that was set for responders," Webster Police Chief Gerald Pickering told reporters.

Firefighters including the two surviving victims were held at bay by the threat of gunfire for about an hour.

One of the men who'd been shot managed to get to his car and drive away from the scene where he met an ambulance and was transported to the hospital for treatment.

Police Special Weapons and Tactics (SWAT) teams responded to the scene and evacuated nearby homes, clearing the area before firefighters could resume fighting the blaze.

The flames spread to at least three more homes and a vehicle by the time fire crews were able to continue fighting the blaze.

"All of our thoughts and prayers go to the families and friends of those who were killed in this senseless act of violence," said New York Governor Andrew Cuom. (IANS)