TOKYO — A UN-adopted nuclear ban treaty is likely to enter into force early next year as the number of signatories is anticipated to reach the needed threshold of 50 soon, possibly later this month, Kyodo quoted a diplomatic source as saying on Friday.

According to the source and the International Campaign to Abolish Nuclear Weapons, or ICAN, 46 countries and regions have completed ratification procedures.

The Treaty on the Prohibition of Nuclear Weapons, adopted in 2017, will enter into force 90 days after it has been ratified by at least 50 countries and regions.

At least four additional countries have already notified the United Nations of their intention to ratify the treaty, the source and the nonprofit organization said, without revealing the names of any such signatories.

The five permanent members of the UN Security Council — Britain, China, France, Russia and the United States, all of which are nuclear powers — have declined to ratify the pact.

Japan, the only country in the world to have experienced nuclear bombings, as well as Germany, have not ratified the pact either, in light of their security alliances with the United States providing nuclear deterrence against adversaries.

Many of the 46 signatories of the nuclear ban pact are small countries in Africa, Asia, Latin America and Oceania. — SPA