As a three-month waiting period North Korea had to observe to officially withdraw from the Nuclear Nonproliferation Treaty ended Thursday, Japan refused to acknowledge the validity of its neighbor's actions.

But it was also trying to walk a fine line and keep from provoking a government that boasts of its nuclear ambitions.

"We do not think there is an international consensus that (North Korea) left the treaty," Chief Cabinet Secretary Yasuo Fukuda said.

Under the provisions of the NPT, signatory nations wishing to leave the pact are required to notify the U.N. Security Council and all the other signatories of their intention three months in advance.

North Korea says it left the NPT Jan. 10 immediately after announcing its withdrawal.

But some countries say North Korea has not notified the other signatories, as required, and thus has not officially withdrawn.

Senior Vice Foreign Minister Toshimitsu Motegi put Japan squarely in this camp during a news conference Thursday.

"Japan has doubts over the validity of North Korea's withdrawal," he said.

But political leaders both in Japan and around the world appear at a loss over what to do next.

A senior Foreign Ministry official said nothing will change after Thursday, an apparent attempt to keep the legal debate over its withdrawal from further stoking the North.

The international community meanwhile is currently leaning toward a soft political solution.

On Wednesday in New York, the U.N. Security Council met to discuss the issue, with members simply expressing "concern."

Initially, they planned to issue a statement condemning North Korea.

Washington had been poised to initiate the censure statement but backed down after Pyongyang said it would consider such a Security Council move a "prelude to war."

The soft approach itself, however, is controversial, as some say allowing North Korea to freely leave the treaty without any condemnation from the international community could cast doubt on the efficacy of the treaty.

"I personally have doubts as to leaving the situation as is," said another ministry official who asked not to be named.

Setting aside legal debate, Fukuda stressed the importance of pressuring Pyongyang to comply with the NPT, freeze all nuclear development facilities and abandon nuclear ambitions.