President Barack Obama urged delegates at a U.N. meeting on Tuesday to put aside differences and strengthen the Nuclear Nonproliferation Treaty so it can deal with the threat of nuclear terrorism and the spread of nuclear weapons.

In a message to a two-week meeting helping to lay the groundwork for a 2010 conference to review the treaty, he called for dialogue and hard work to ensure that the NPT remains the cornerstone of global disarmament and nonproliferation efforts and "continues to make an enduring contribution to international peace and security."

The last NPT review conference in 2005 failed to make substantive progress because of bickering over procedural issues. But Obama's pledge last month in Prague to reduce and eventually eliminate nuclear weapons _ which won praise Monday from China and developing countries _ has spurred hope that the new U.S. policy and new U.S.-Russian cooperation will end a long deadlock on global disarmament efforts.

Obama's message was read to delegates by Rose Gottemoeller, the U.S. assistant secretary of state for verification, compliance and implementation, who said the United States wants a review process with balanced emphasis on the treaty's three pillars _ disarmament, nonproliferation and peaceful uses of nuclear energy.

The NPT requires signatory nations not to pursue nuclear weapons in exchange for a commitment by the five nuclear powers _ the U.S., Russia, Britain, France and China _ to move toward nuclear disarmament. It also gives all treaty members the right to develop peaceful programs to produce nuclear power.

"We must strengthen the NPT to deal effectively with the threat of nuclear weapons and nuclear terrorism," Obama said. "Action is needed to improve verification and compliance with the NPT and to foster the responsible and widest possible use of nuclear energy by all states."

In a joint declaration on April 1, Obama and Russian President Dmitry Medvedev ordered negotiators to start work on a new treaty to reduce their nuclear stockpiles as a first step towards "a nuclear-weapon-free world."

Gottemoeller, who heads the American team negotiating the arms reductions, said she and her Russian counterpart would hold a second meeting in Moscow after the U.N. meeting ends. And she pledged her "best efforts" to meet the goals set by the U.S. and Russian leaders to report on progress by July and to reach agreement before the current strategic arms-control treaty expires in December.

The U.S. president also promised to seek speedy Senate ratification of the nuclear test ban treaty, to pursue universal ratification of the NPT, and to launch a global effort at the Conference on Disarmament in Geneva to adopt a new treaty that would end production of fissile material used to produce nuclear weapons, including uranium and plutonium.

A fissile material cutoff treaty would not only fulfill NPT commitments, "but it also could help avoid destabilizing arms races in regions such as south Asia," Gottemoeller said. "And by limiting the amount of fissile material worldwide, (it) could facilitate the task of securing such weapons-usable materials against theft or seizure by terrorist groups."

She said there are currently 190 countries that are parties to the NPT and the U.S. is encouraging the three holdouts _ India, Pakistan and Israel _ to join the treaty, and North Korea to come back.

"I would say India is coming closer to the non-proliferation regime," Gottemoeller said, citing its willingness to support a ban on nuclear testing, a cutoff on production of fissile material and better export controls.

Stopping the spread of nuclear weapons will give countries with nuclear weapons confidence that further reductions in their nuclear arsenals can be made without undermining their security, she said.

Gottemoeller said the review conference must also propose ways to develop "effective consequences" for those who violate the NPT.

While the U.S. supports the right of all countries to benefit from the peaceful use of nuclear energy, she stressed that they also have important obligations _ "and of course that applies to all the treaty signatories including Iran."

While Iran insists its nuclear program is peaceful and aimed only at producing nuclear energy, the U.S. and key European nations are concerned that Tehran's real goal is to produce nuclear weapons. Suspicions bred by Tehran's nearly two decades of clandestine atomic activities led the U.N. Security Council to impose sanctions against Iran over its refusal to halt uranium enrichment.