Pope Francis has urged more nations to join a U.N. treaty banning nuclear weapons, saying their prohibition is badly needed to promote peace today.

Addressing his weekly general audience Francis said that I strongly encourage all states and all people to work with determination to promote the conditions necessary for a world without nuclear weapons, thus contributing to the advancement of peace and multilateral cooperation, which humanity needs so very much today.

The United States, Britain, France and other nuclear powers have not signed the treaty and boycotted talks that led to it.