President Donald Trump said he was looking into the issue of selling guns manufactured by 3-D printers, appearing critical of the idea.

“I am looking into 3-D Plastic Guns being sold to the public,” Trump wrote. “Already spoke to NRA, doesn’t seem to make much sense!”

The president reacted to the issue after gun control activists raised awareness of gun hobbyists sharing ideas for 3-D printed gun parts online.

The State Department settled a lawsuit from Cody Wilson’s Defense Distributed in July, allowing his company to share online files about gun printing.

The left argues that 3-D printed guns are a threat to the public, allowing criminals to obtain untraceable guns. Gun hobbyists argued that building their own guns is protected by the Second Amendment.