President Bush today warned North Korea not to share its nuclear knowledge with other countries or with terrorist groups, saying such an act would be considered a grave threat to the US.

Tackling the problem of North Korea, which tested a nuclear weapon for the first time in October but has since shown a willingness to return to international talks, is at the top of the agenda on Mr Bush's current tour of Asia.

Speaking on the first stage of his trip, in Singapore, Mr Bush urged Asian leaders to stay firm in the face of provocation from North Korea and to enforce the UN Security Resolution passed in the days after the nuclear test. The resolution allows UN members to inspect cargo coming to and from the erratic, Stalinist state, but since its passing, South Korea, a key US ally, has balked at the idea.

"The transfer of nuclear weapons or material by North Korea to states or non-state entities would be considered a grave threat to the United States and we would hold North Korea fully accountable for the consequences of such action," said Mr Bush at the National University of Singapore.

"For the sake of peace, it is vital that the nations of this region send a message to North Korea that the proliferation of nuclear technology to hostile regimes or terrorist networks will not be tolerated," he said.

Mr Bush is being accompanied on his three-nation, eight-day Asian tour by the US Secretary of State, Condoleezza Rice. Their next stop is a summit of the 21-nation Asia Pacific Economic Cooperation (Apec) in Vietnam, where Mr Bush is planning to hold bilateral talks with leaders including Vladimir Putin of Russia, Hu Jintao of China and the new Japanese Prime Minister, Shinzo Abe.

Today, Ms Rice spent the day in talks with Apec foreign ministers, discussing what has been described as a "carrots and sticks" policy to coax North Korea back into the international fold.

Mr Bush said that the ministers were committed to reviving the Six Party Talks, which failed a year ago when North Korea stormed out to protest US attempts to crack down on its money laundering. He said that the five countries — China, Russia, Japan the US and South Korea — charged with negotiating with Pyongyang were "speaking with one voice."

"The only way for North Korea to move forward, for the good of their people, is to abandon its nuclear weapons programs and rejoin the international community," he said.

In general remarks, Mr Bush stressed that America's long-term interests in Asia remained as strong ever, despite the growing power and increasingly activist foreign policy of China and his Republican party's chastening experience at the hands of American voters last week.

"We must maintain our presence in the Pacific. We must seize on our common opportunities. We must be willing to confront our common threats. And we must help our partners build more hopeful societies throughout this vital part of the world," he said.

• French customs officers today searched a North Korean ship in the small Indian Ocean territory of Mayotte. A spokesman for the French Foreign Ministry declined to name the ship, its destination or cargo, but said officers were carrying out "a complete and thorough inspection of merchandise and personnel" on the small island between Madagascar and the coast of Mozambique. It appeared to be the first time that France had inspected a North Korean ship since the passing of the UN Security Council resolution last month.

Times Recommends

• Zardari still has to tackle tough questions
• Material evidence 'debunks' Turin Shroud
• BBC criticised over Uganda gay execution poll