New York’s sheriffs have been outspoken in their opposition to the state’s new gun-control law.

Now the nation’s big-city police chiefs are wading into the legal fight.

And they support the SAFE Act.

“Assault weapons are enablers of violent crime and mass murder,” the Major City Chiefs Association said in a friend-of-the-court brief filed in U.S. District Court in Buffalo.

The association, which counts Buffalo Police Commissioner Daniel Derenda and 62 other urban police chiefs as members, views the new law as an important step in curbing the illegal use of assault weapons.

So does Rochester’s police chief, who filed his own brief in support of the law.

Chief James M. Sheppard pointed to last year’s Christmas Eve ambush that killed two volunteer firefighters, one of them a police officer, and wounded two others in the Rochester suburb of Webster.

Sheppard said the gunman, who took his own life before he could be captured, used the same type of Bushmaster assault rifle that was used to kill 26 people earlier in December at Shady Hook Elementary School in Newtown, Conn.

“The type of semiautomatic rifle used in Webster ... is now banned as an assault weapon under the SAFE Act,” he said in his brief.

The briefs filed by Sheppard and the police chiefs, who were joined by two other groups, are the latest developments in a lawsuit challenging the five-month-old law.

Derenda, a member of the chiefs association, could not be reached to comment, but a source close to the commissioner said he intends to enforce the law.

The suit, filed in Buffalo federal court by the New York State Rifle and Pistol Association, claims the law violates an individual’s right to keep and bear arms under the Second Amendment.

The new briefs also suggest that when it comes to the SAFE Act, there’s a wide rural versus urban chasm in New York’s law enforcement community.

“Certainly guns are more of a concern in urban areas,” Erie County Sheriff Timothy B. Howard said Monday. “Unfortunately, they made a one-size-fits-all law, and that never works.”

Howard, who has been vocal in his opposition to the law and has vowed not to enforce it, said he is not surprised by the chiefs’ stance on the law.

Like Sheppard, he filed a brief, although his supports overturning the SAFE Act.

Howard, who was joined in his opposition by the New York Sheriffs Association, thinks the law is an infringement on the Second Amendment and a blow to law-abiding citizens, especially gun owners.

“I really wish we could go back to square one,” he said Monday,

The SAFE Act, pushed through the State Legislature following the Sandy Hook shootings, includes an expansion of New York’s assault weapons ban.

It also requires mental health professionals to report the names of patients they think are a threat to themselves or others and gives the state authority to confiscate weapons if they have them.

Mental health experts claim the provision will create a chilling effect on people who need professional help but might otherwise avoid it because their weapons might be taken away.

The police chiefs, in their brief, said the link between mass murder and assault weapons is undeniable.

“Mass slaughters terrorize society at large, undermine the public’s sense of safety and security, and burden the community with latent fear and uncertainty,” the group said in its brief.

It also challenged the notion that the new law violates the Constitution.

The Second Amendment “does not protect dangerous and unusual weapons,” the chiefs said, “It protects only weapons that are in common use for lawful purposes.”

Sheppard agreed and cited crime statistics indicating that Rochester had the third-highest rate of violent crime in the state outside of New York City.

“With over 32 years as a law enforcement officer in the City of Rochester,” he said, “I have witnessed firsthand the devastating effects of gun violence on victims, families and neighborhoods.”

Sheppard and the police chiefs are not the only groups and individuals asking Chief U.S. District Judge William M. Skretny, who is hearing the case, to reject the rifle association’s request for an injunction blocking enforcement of the law.

Briefs also were filed by the Brady Center to Prevent Gun Violence, one of the country’s most influential gun-control advocates, as well as several nationally known researchers involved in the study of gun violence.