The National Rifle Association (NRA) has filed a lawsuit against Massachusetts Governor Charlie Baker and Attorney General Maura Healy over the Bay State's ban on assault weapons. The NRA's Massachusetts affiliate contends that the ban is unlawful and must be declared "void and unenforceable".

The 33-page civil complaint was filed in a Boston federal court by the Gun Owners' Action League and other plaintiffs against the state. The lawsuit claims that the state's definition of assault weapons is a "non-technical, entirely fabricated, and political term of uncertain definition and scope," The Boston Globe reported.

Baker, a Republican, and Healy, a Democrat, are named as defendants along with the state's public safety secretary and the State Police. Plaintiffs claim that the state's ban illegally includes the sale or possession of assault weapons such as AR-15 and AK-47 models.

According to The Globe, the lawsuit was partly prompted by Healy's July order to reinforce the ban on so-called "copy-cat" firearms. The directive "vastly expanded Massachusetts' prohibition to ban an entire class of popular firearms commonly kept for lawful purposes," the lawsuit claims.

Jay Porter, an attorney for the plaintiffs, said the complaint was filed in response to what he referred to as the heightened animosity towards legal gun ownership in the deeply blue state. "The level of hostility to the gun-owning public in the state of Massachusetts has grown to be intolerable," Porter told the Globe.

Porter added: "Our position is that the state doesn't have the authority under the Second Amendment to ban firearms that are commonly kept by responsible law abiding citizens for lawful purposes. ... The Supreme Court has told us emphatically that the government cannot ban popular firearms which are commonly kept for lawful purposes."

The plaintiffs hope to have a federal judge declare Massachusetts' assault weapon ban, which was first passed in 1998, and Healy's directive unconstitutional.

Healy's spokeswoman, Jillian Fennimore, told the Globe that "the assault weapons ban keeps dangerous, military-style weapons off our streets." In an email, Fennimore added: "Since our office issued the enforcement guidance last July, sales of illegal assault weapons have ended in Massachusetts. This new lawsuit ... seeks to overturn this 20-year-old law. We will vigorously defend the law."

Boston Magazine reported that Healy faces a separate lawsuit over her directive on "copy-cat" assault rifles. That lawsuit was filed by four gun stores and a national firearms trade group.

Meanwhile, Baker's spokeswoman said the governor "supports the Second Amendment to our Constitution and Massachusetts' gun laws, including the ban on assault weapons, and the administration generally does not comment on pending lawsuits."