Sen. Dianne Feinstein, D-Calif., a longtime advocate of tougher gun regulations, said Sunday that it was not clear what rules could have prevented the tragic shooting in Las Vegas last week. She nevertheless called for further regulations in the wake of the tragedy.

"I don't know. I would have to take a good look at that," Feinstein responded when asked on NBC's "Meet the Press" what regulations could have prevented the mass shooting at the Mandalay Resort and Casino that claimed the lives of 58 concert-goers. "I am not sure there is any set of laws that could have prevented it."

The senator noted that the shooter, gambler Stephen Paddock, had obtained his guns legally. The lawmaker nevertheless said that the regulations for ownership should be tighter. She has co-sponsored legislation that would prohibit so-called "bump stocks," which allow non-automatic weapons to fire faster than they would otherwise. "Possession of machine guns is not legal under the Second Amendment."

Feinstein compared the regulations to issuing driver's licenses. "The [National Rifle Association] says that guns don't kill people. People kill people. Well, cars don't kill people. People driving cars kill people," the senator said.

The lawmaker lamented the state of debate on the issue. "The state is sad. America is a gun-happy country. I think there are many of us, growing numbers, that don't want a gun-happy country."