South Korea has stressed that it will not tolerate North Korea's pursuit of nuclear ambitions.

The warning followed Pyongyang's announcement Thursday that it has nuclear weapons and is withdrawing indefinitely from the six-way nuclear talks.

In a statement issued after a meeting of the National Security Council, the Seoul government expressed its deep concern over the North's announcement. The statement said the North's declaration to strength its nuclear might is of no help to efforts to denuclearize the Korean Peninsula and resolve the nuclear issue through dialogue.

Seoul urged Pyongyang to return to the nuclear discussions, saying that it should present its differences in opinion with Washington at the negotiating table.

In particular, the government vowed to actively seek prompt resumption of the nuclear discussions and hold close consultation with the United States and other allies on how to deal with the North's recent revelation.

Earlier on Thursday, in a statement carried by the official KCNA News Agency, the North's Foreign Ministry said that Pyongyang has manufactured nukes to cope with the Bush administration's increasingly undisguised policy to isolate and stifle the North.

The statement marked the first time the North has publicly said it has nuclear weapons. It's also Pyongyang's first response regarding the nuclear talks since U.S. President George W. Bush said in his inauguration speech on Jan. 20 that he was committed to ending tyranny.