Washington state Governor Jay Inslee Tuesday signed House Bill (HB) 1240, prohibiting the sale, manufacture, import and distribution of assault weapons in the state.

The ban includes AR-15s, AK-47s and many other kinds of semiautomatic weapons. According to the bill, “[a]ssault weapons are civilian versions of weapons created for the military and are designed to kill humans quickly and efficiently.” The bill exempts the sale of these weapons to armed forces branches and law enforcement agencies.

Though the ban went into effect immediately on Tuesday, it has already seen its first legal challenge. A Vancouver gun store joined the Second Amendment Foundation and the Firearms Policy Coalition in bringing a lawsuit challenging the constitutionality of the ban and seeking injunctive relief. The complaint alleges that Washington “has criminalized one of the most common and important means by which its citizens can exercise their fundamental right to self-defense.”

In response to the lawsuit, Washington Attorney General Bob Ferguson, a dedicated supporter of the ban, expressed his confidence that the law will survive judicial review.

In addition to HB 1240, Governor Inslee also signed two other bills on Tuesday advancing gun control. HB 1143 requires safety training and a 10-day waiting period to purchase firearms, and Senate Bill (SB) 5078 asserts greater legal responsibility on gun sellers and manufacturers.

Tuesday’s actions add Washington to a short but growing list of US state governments enacting gun control measures.