Sen. Dianne Feinstein, D-Calif., said Friday that the Bureau of Alcohol, Tobacco, Firearms and Explosives will never regulate "bump stocks," and that new legislation will be needed to impose a ban or other limits on the firearms accessory.

"The ATF does NOT have the authority to address bump-fire stocks — and has made this point clear to Congress MULTIPLE times," Feinstein tweeted Friday.

Her message is consistent with signals that House lawmakers received last week during a meeting with the ATF. House aides said this week that ATF officials indicated that legislation is the only way for new limits on bump stocks.

Bump stocks became an issue after the Las Vegas shooting, where police reportedly found the accessory in the room of the shooter. The accessory uses the recoil action of a semi-automatic weapon to increase its rate of fire.

The National Rifle Association proposed a new rule from the ATF in the wake of the Las Vegas shooting, as did several Republican lawmakers.

But if that option is as closed off as Feinstein and other lawmakers believe, the federal government will likely be at a standstill.

Legislation seems highly unlikely under the Republican leadership in the House and Senate.

Feinstein said in an op-ed for The Hill that ATF has held this position for years.

"[T]he ATF made clear in a 2010 letter to a leading weapons manufacturer and again in a 2013 letter to Congress that it lacks the authority to regulate bump fire stocks under the Gun Control Act or National Firearms Act," she wrote. "The agency detailed that bump-fire stocks are legally not considered machine gun conversion devices and 'are not subject to the provisions of federal firearms statutes.'"

Feinstein and others have proposed legislation banning any device that speeds up the rate of fire of a semi-automatic weapon.

"Such legislation can and will save lives, and Congress should act as soon as possible," she wrote. "It's been just two weeks since 58 concertgoers were gunned down. We owe it to them to not just move on."