Kofi Annan urged 11 key countries, including the United States, to ratify the nuclear test-ban treaty so it can finally take effect.
Opening a conference Wednesday to spur the treaty's entry into force, Secretary-General Annan said all countries should be gravely concerned that nine years after the treaty was opened for signatures, it still hasn't entered into force.
"The longer entry into force of the treaty is delayed, the greater the risk that someone, somewhere, will test nuclear weapons," he warned. "That would be a major setback for the cause of non-proliferation and disarmament."
Since the Comprehensive Nuclear Test Ban Treaty opened for signatures in September 1996, it has been signed by 175 countries and ratified by 123 countries.
But it will only take effect when 44 countries that participated in the Conference on Disarmament in 1996 and possessed nuclear research and power reactors have ratified it. To date, 33 of the 44 countries have ratified the treaty, but there seem little prospects of getting all 11 holdouts to change their positions.
The United States has signed the treaty, but it has not been ratified by the U.S. Senate. U.S. President George W. Bush's administration opposes it and is boycotting the three-day conference. Other countries that have refused to ratify the treaty include Pakistan, India, Israel and North Korea all of which are believed to have nuclear weapons.
An explosion of household gas occurred in a nine-storeyed apartment building in the city of Shakhty, the Rostov region of Russia. The blast destroyed two storeys of the building