The preparatory commission for the Comprehensive Nuclear Test Ban Treaty on Friday welcomed the recent ratification of the pact by Thailand and a new signing by the Polynesian island nation of Tuvalu.

Bangkok, which ratified the treaty in September, became the 167th state to do so. This also marked the ratification of the pact by all 10 members of the Association of Southeast Asian Nations.

ASEAN has a separate accord called the Southeast Asia Nuclear-Weapon-Free Zone Treaty, in effect since 1997, which declares Southeast Asia a nuclear weapon-free zone and asks the five recognized nuclear powers -- Britain, China, France, Russia and the United States -- to pledge not to use such weapons in the region.

The CTBT aims to establish a verifiable global ban on all types of nuclear explosive tests. Including Tuvalu, the pact has been signed by 184 countries.

To take effect, the CTBT must be signed and ratified by the 44 countries that had nuclear reactors for research or power generation while the treaty was under negotiation. Eight of those states -- the United States, China, Egypt, India, Iran, Israel, North Korea and Pakistan -- have yet to ratify it.