Trump slams 'gun-free zones' in Chattanooga shooting

Republican presidential candidate Donald Trump said the four Marines who were killed in Thursday's shooting at a Navy reserves facility in Chattanooga "never had a chance" and called for an end to gun-free zones.

Many on Twitter noted an image of a sign prohibiting guns at the site in the wake of the shooting.

This is not the first time a mass shooting at a military installation has sparked criticism among gun-rights supporters.

After the September 2013 Navy Yard shooting, some -- such as Oliver North -- blamed a 1993 regulation implemented during the Clinton administration  for establishing the policy.

The liberal group Media Matters for America countered, saying that the order in question was actually the product of a directive issued by the Pentagon under the presidency of Republican George H.W. Bush, and that it still allowed for certain personnel to carry firearms.