The UN announced Saturday that 50 countries have now ratified a treaty seeking to destroy all nuclear weapons and permanently ban their use—the minimum number required for the treaty to become law.

The UN completed negotiations on the Treaty on the Prohibition of Nuclear Weapons at its New York headquarters in July 2017. The treaty constitutes “a legally binding instrument to prohibit nuclear weapons, leading to their total elimination.” Following negotiations, the treaty was open to signatories beginning in September 2017.

The treaty prohibits state parties from “developing, testing, producing, manufacturing, or otherwise acquiring, possessing or stockpiling nuclear weapons or other nuclear explosive devices.” It further bans countries from making threats of use.

On Saturday, Honduras joined Jamaica, Nauru and Tuvalu as the most recent countries to ratify the treaty. Governments representing 84 countries have signed the treaty, and of those, 50 have ratified or accepted it. The US and the world’s eight other nuclear powers—Russia, China, Britain, France, India, Pakistan, North Korea and Israel—have not signed the treaty.

With the fiftieth ratification, the treaty will enter into force on January 22, 2021. In an official statement, UN Secretary-General’s spokesperson Stéphane Dujarric said that the entry into force represents “the culmination of a worldwide movement to draw attention to the catastrophic humanitarian consequences of any use of nuclear weapons.”