PARIS, Jan. 27 -- France Saturday staged the sixth and most powerful in its controversial series of underground nuclear tests in the South Pacific, the Defense Ministry announced. It said the blast took place at 2130 GMT (4:30 p.m. EST) on Fangataufa Atoll and had a strength of about 120 kilotons -- more than six times the size of the explosion blast that destroyed Hiroshima in 1945. The test was aimed at 'ensuring the reliability' of France's nuclear weapons, the Defense Ministry statement said. It was the most powerful of the six tests that France has carried out in French Polynesia since September. The statement gave no indication whether the latest explosion would be the last. The government has said the series will be concluded before the end of February, but has left unclear whether there will be six or seven tests. President Jacques Chirac announced in June that France would break a 3-year moratorium by four of the five nuclear powers and carry out a limited series of nuclear tests in the South Pacific. He said France will then sign the Comprehensive Test Ban Treaty that is to outlaw all future nuclear testing. Chirac says the tests are necessary to verify France nuclear arsenal, but they have provoked international condemnation, in particular from South Pacific nations. The first test, on Sept. 5, sparked two days of rioting in the French Polynesian capital of Papeete. Saturday's explosion was the second at Fangataufa Atoll, which is used for the more powerful blasts aimed at helping to prove the reliability of France's nuclear weapons.
The four smaller blasts were staged on nearby Mururoa Atoll to help perfect a system of computer simulation of future tests. A Japanese newspaper recently reported that French experts have found traces of a toxic radioactive substance during the current series of tests. France denied the report, and insisted the explosions pose no danger to the region's environment.