In a press conference shortly after 11 a.m. this morning in Washington, D.C., five senators, led by California Sen. Dianne Feinstein and including Connecticut Sens. Richard Blumenthal LAW ’73 and Chris Murphy, introduced legislation that would re-establish a federal ban on assault weapons.

The legislation, known as the Assault Weapons Ban of 2013, will seek to dramatically expand the definition of assault weapons and ban the sale, transfer, importation or manufacturing of those weapons. Beyond specifying 120 firearms, it defines assault weapons as semi-automatic rifles, handguns or shotguns that can accept a detachable magazine and have at least one military characteristic, and semi-automatic rifles and handguns with fixed magazines that accept more than 10 rounds.

The legislators were joined by two congressmen, Philadelphia Mayor Michael Nutter, Philadelphia Police Commissioner Charles Ramsey and the Very Rev. Gary R. Hall of the National Cathedral in Washington, D.C. Also in attendance were several law enforcement officers, gun-safety advocates, doctor and teacher organizations and victims of gun violence.

The proposed assault weapons ban is opposed by the National Rifle Association, along with numerous other gun-rights organizations, and is likely to face an uphill battle in Congress over the coming months.

In the wake of the Dec. 14 mass shooting at Sandy Hook Elementary School in Newtown, Conn., President Obama has voiced support for an assault weapons ban, along with enhanced background checks and several other proposals meant to curb gun violence. In his inaugural speech on Monday, Obama placed gun control as one of the central tenants of his second term.