A convicted felon has shot dead two firefighters and wounded two others after luring them to a blaze that police
said he had apparently set as a trap in a small town in New York state, officials said.
The 62-year-old shooter - who was found guilty of manslaughter and was jailed for 17 years for his grandmother's death in 1980 - then fatally shot himself in the head, said police in Webster, on the shores of Lake Ontario.
The incident - which comes as debate rages in the United States about gun control following the Newtown school massacre - happened shortly before 6:00am local time (11:00 GMT) on Monday in the suburb of Rochester.
"The responding firefighters, when they pulled up at the scene, were fired upon," Webster police chief Gerald Pickering told a press conference.
"Four of the firefighters were shot. Two are deceased, two were transported to area hospitals," he said.
Pickering said it appeared there was only one shooter, and that the suspect was found dead at the scene.
The two wounded firefighters were listed in guarded condition at a local hospital, according to the Democrat and Chronicle newspaper.
Monroe county sheriff Patrick O'Flynn said there was no longer any "active shooting" at the scene, where a security cordon was put up and 33 residents were evacuated. But firefighters were still battling to contain the blaze.
The incident in Webster comes 10 days after the shooting rampage at an elementary school in Newtown, Connecticut , in which 20 children, aged six and seven, and six adults were killed.
The shooter, Adam Lanza, killed his mother at their home before heading to the school, where he eventually took his own life.
The Newtown shooting has revived debate in the US on the country's gun laws, which are far more lax than in most other developed nations.
Barack Obama, the US president, said he would support a new bill to ban assault rifles, and has put Vice President Joe Biden in charge of a panel looking at a wide range of other measures, from school security to mental health.
Democratic Senator Dianne Feinstein has pledged to introduce a bill in January that would ban at least 100 military-style semi-automatic assault weapons, and would curb the transfer, importation and the possession of such arms.
The US has suffered an increase of gun violence over the last three decades, including 62 mass shooting incidents since 1982.