[JURIST] UN Secretary General Kofi Annan [official profile] on Wednesday called on nations to quickly sign and ratify the Comprehensive Nuclear Test Ban Treaty [PDF text] as he opened the fourth conference [CTBTO backgrounder] on bringing the treaty into force. Annan said countries' inability to agree on the issue was a "significant failure" that the world should be "gravely concerned about." A week after a major UN summit failed to address [JURIST report] nuclear non-proliferation, Annan and representatives of Canada, Australia, Kazakhstan and the UK urged ratification of the treaty to prevent future testing of nuclear weapons. Among the issues expected to be discussed at the conference which continues through Friday is the creation of a verification system that could also be used for early detection of tsunamis. The comprehensive test-ban treaty, originally signed in 1996, has collected 176 signatures, but has been ratified by only 33 of the 44 nuclear powers necessary for it to take effect. The US has signed but not yet ratified the treaty [JURIST report]; other key countries such as Pakistan, India and North Korea have not even signed it. Read Annan's complete conference statement [PDF text]. AFP has more.