House Speaker Paul Ryan said Thursday that Congress must weigh banning “bump stocks,” devices that accelerate the firing power of semi-automatic weapons and were used in the Las Vegas shooting that left 59 people dead on Sunday.

“Fully automatic weapons have been outlawed for many years,” Ryan, R-Wis., told reporters at a press conference at a factory in Maryland’s Eastern Shore. “This seems to be going around that, so we need to look at tightening up this requirement so we are in compliance with the law.”