Leaders Gather for Nuclear Talks as New Threat Is Seen

The message of those photos was clear: While Pakistan struggles to make sure its weapons and nuclear labs are not vulnerable to attack by Al Qaeda, the country is getting ready to greatly expand its production of weapons-grade fuel.

The Pakistanis insist that they have no choice. A nuclear deal that India signed with the United States during the Bush administration ended a long moratorium on providing India with the fuel and technology for desperately needed nuclear power plants.

Now, as critics of the arrangement point out, the agreement frees up older facilities that India can devote to making its own new generation of weapons, escalating one arms race even as President Obama and President Dmitri A. Medvedev of Russia sign accords to shrink arsenals built during the cold war.

Mr. Obama met with the leaders of India and Pakistan on Sunday, a day ahead of a two-day Washington gathering with 47 nations devoted to the question of how to keep nuclear materials out of the hands of terrorists. In remarks to reporters about the summit meeting, Mr. Obama called the possibility of a terrorist organization obtaining a nuclear weapon “the single biggest threat to U.S. security, both short-term, medium-term and long-term.”

The summit meeting is the largest gathering of world leaders called by an American president since Franklin D. Roosevelt organized the 1945 meeting in San Francisco that created the United Nations. (He died two weeks before the session opened.) But for all its symbolism and ceremony, this meeting has quite limited goals: seeking ways to better secure existing supplies of bomb-usable plutonium and highly enriched uranium. The problem that India and Pakistan represent, though, is deliberately not on the agenda.

“President Obama is focusing high-level attention on the threat that already exists out there, and that’s tremendously important,” said Sam Nunn, the former Democratic senator from Georgia who has devoted himself to safeguarding global stockpiles of weapons material — enough, by some estimates, to build more than 100,000 atom bombs. “But the fact is that new production adds greatly to the problem.”

Nowhere is that truer than Pakistan, where two Taliban insurgencies and Al Qaeda coexist with the world’s fastest-growing nuclear arsenal. According to a senior American official, Mr. Obama used his private meeting Sunday afternoon with Yousaf Raza Gilani, Pakistan’s newly empowered prime minister, to “express disappointment” that Pakistan is blocking the opening of negotiations on a treaty that would halt production of new nuclear material around the world.

Experts say accelerated production in Pakistan translates into much increased risk.

“The challenges are getting greater — the increasing extremism, the increasing instability, the increasing material,” said Rolf Mowatt-Larssen of the Kennedy School of Government at Harvard, who as a C.I.A. officer and then head of the Energy Department’s intelligence unit ran much of the effort to understand Al Qaeda’s nuclear ambitions.

“That’s going to complicate efforts to make sure nothing leaks,” he said. “The trends mean the Pakistani authorities have a greater challenge.”

Few subjects are more delicate in Washington. In an interview last Monday, Mr. Obama avoided a question about his progress in building on a five-year, $100 million Bush administration program to safeguard Pakistan’s arms and materials.

“I feel confident that Pakistan has secured its nuclear weapons,” Mr. Obama said. “I am concerned about nuclear security all around the world, not just in Pakistan but everywhere.” He added, “One of my biggest concerns has to do with the loose nuclear materials that are still floating out there.”

Taking up the Pakistan-India arms race at the summit meeting, administration officials say, would be “too politically divisive.”

“We’re focusing on protecting existing nuclear material, because we think that’s what everyone can agree on,” one senior administration official said in an interview on Friday. To press countries to cut off production of new weapons-grade material, he said, “would take us into questions of proliferation, nuclear-free zones and nuclear disarmament on which there is no agreement.”

Mr. Obama said he expected “some very specific commitments” from world leaders.

“Our expectation is not that there’s just some vague, gauzy statement about us not wanting to see loose nuclear materials,” he said. “We anticipate a communiqué that spells out very clearly, here’s how we’re going to achieve locking down all the nuclear materials over the next four years, with very specific steps in order to assure that.”

Those efforts began at the end of the cold war, 20 years ago. Today officials are more sanguine about the former Soviet stockpiles and the focus is now wider. Last month, American experts removed weapons-grade material from earthquake-damaged Chile.