WASHINGTON (AP) — The Trump administration is moving to officially ban bump stocks, which allow semi-automatic weapons to fire rapidly like automatic firearms.

A senior Justice Department official says bump stocks will be banned under the federal law that prohibits machine guns. It will take effect in late March. After that, it will be illegal to possess bump stocks.

The official wasn’t authorized to discuss the matter publicly and spoke to The Associated Press on condition of anonymity.

The devices became a focal point in the national gun control debate after they were used in October 2017 in the deadliest mass shooting in modern U.S. history. Gunman Stephen Paddock rained a hail of bullets from his 32nd-floor Las Vegas hotel room, killing 58 people at a concert.