The US undersecretary of state said he had extensive discussions with his Chinese counterpart on President George W. Bush's recent proposals to improve international non-proliferation efforts, specifically the proposal to expand the Proliferation Security Initiative (PSI), which aims to intercept weapons shipments.

Bolton said Beijing shared similar goals with Washington on wanting to stem proliferation, and has cooperated with the United States on non-proliferation efforts, including weapons seizures.

"Both China and the United States obviously are firmly opposed to proliferation of weapons of mass destruction and their means of delivery," Bolton told reporters.

"We stand ready to enhance cooperation in such areas as information (intelligence) exchange.... China shares the nonproliferation principles and objectives of those countries participating in PSI ..."

However, Bolton, who is in charge of arms control and international security, said Beijing has also been found to have participated in proliferation of chemical weapons and ballistic missiles.

The Bush administration has not "wavered" in imposing economic sanctions against China in such circumstances, he said.

"In fact, we've imposed more sanctions on China and more sanctions generally in just the first three years ... of the Bush administration than the entire Clinton administration in all eight years," Bolton said.

On Sunday, the Washington Post said US government officials and arms experts released documents which showed dramatic evidence of China's long suspected involvement in Pakistan's nuclear program.

It said the documents were found in Libya, some of which included text in Chinese, and contained detailed, step-by-step instructions for assembling an implosion-type nuclear bomb that could fit atop a large ballistic missile.

The designs were sold to Libya by a Pakistani-led nuclear trading network that is now the focus of an expanding international probe, the daily reported.

Bolton confirmed weapons designs were found but refused to comment on reports of Chinese involvement.

US intelligence officials concluded years ago that China aided Pakistan in building its first nuclear weapon until the 1980s.

China's foreign ministry did not respond to phone calls Monday but last week denied it was involved in proliferation.

Bolton said he and Chinese Vice Foreign Ministery Zhang Yesui also discussed China's wish for the European Union to lift an embargo imposed by the EU on arms sales slapped on China after 1989 Tiananmen Square massacre.

But he said the United States has no plans to lift a similar embargo it imposed on China.

"We did discuss the EU weapons embargo and whether or to what extent the Europeans are going to modify it. That's a decision the Europeans will reach. Our view is we're not going to modify our weapons embargo ...," Bolton said.

French President Jacques Chirac has called for an end to the EU embargo, saying that it no longer makes sense, but Washington has cited ongoing human rights violations as reason to keep the embargo.

Bolton also discussed the North Korean nuclear issue with Chinese Vice Foreign Minister Wang Yi, and Monday said "the ball was in their (the North's) court in terms of how well the second round of six-nation talks to convince the North to abandon its nuclear weapons program, will go.

The talks are scheduled to open in Beijing next Wednesday.

"The issue really is whether North Korea is prepared to make the commitment for the complete, verifiable, irreversible dismantlement of its program," Bolton said.

He declined to say whether he was optimistic the talks will bring about concrete results, unlike the first round which ended inconclusively last August.

"I'm neither an optimist nor a pessimist. I'm a realist," Bolton said, adding: "Our position is going to be substantively the same as it was before and that is the complete, verifiable and irreversible dismantlement of the program."

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