Senate Majority Leader Harry Reid said on Tuesday he lacked the votes to bring gun-control legislation to the Senate floor for a vote."We’re going to move this up as quickly as we can, but we’ve got to have the votes first," the Nevada Democrat told The Hill . "We don't have the votes. I hope we get them, but we don't have them now."Reid's comments came in the wake of the slaying of 12 people in a shooting at the Washington Navy Yard.The gunman, Aaron Alexis, 34, a former Navy reservist who was an information technology employee with a defense contractor, was killed at the scene. The FBI said on Tuesday that he entered the Navy Yard armed with a shotgun.Alexis, whom authorities said had an arrest record, had been hearing voices and was being treated by Veterans Affairs for mental problems in the weeks before the shooting rampage, FBI officials said.He was not, however, stripped of his security clearance, the FBI said.The mass shooting was the deadliest on a military installation in the United States since the attack at Fort Hood, Texas, in 2009.Reid on Tuesday called for expanded background checks to prevent people with mental illness from obtaining guns."Background checks," he said, according to The Hill. "We want to stop people who have mental illness from buying a gun. We want to stop people who are felons from being able to purchase a gun."An amendment sponsored by GOP Sen. Pat Toomey of Pennsylvania and Democratic Sen. Joe Manchin of West Virginia to expand background checks fell six votes of advancing in April.Democrats have since shelved gun-violence legislation, The Hill reports.Some lawmakers, however, have discussed moving a bill narrowly tailored to focus on mental illness, according to The Hill, but Reid said it was not practical to separate it from expanded background checks.When asked if it's possible to prevent the mentally ill from obtaining firearms, Reid responded: "No, you can't. You have to have background checks.""I’ve talked to people consistently — and the thing that bothers me is the number of Republicans who say, 'Yeah, we know you’re right, but we can’t do anything about it,'" Reid said, referring to the lobbying power of the National Rifle Association and other gun-rights groups.