Former world leaders and arms-control negotiators joined entrepreneur Sir Richard Branson and the queen of Jordan Tuesday to launch a project aimed at eliminating the world's nuclear weapons over the next 25 years.

The group wants to reach the impossible-sounding goal by reviving nuclear disarmament efforts that have lagged since the end of the Cold War. It is proposing deep cuts in U.S. and Russian nuclear arsenals, a worldwide verification and enforcement system and phased reduction leading to elimination of all stockpiles.

"We have to set an example," Branson said.

The group, called Global Zero, wants to start with U.S.-Russian negotiations to cut back nuclear stockpiles. Then a second phase would bring in countries such as China, Britain and France. Finally, it hopes to attract other countries such as Iran — which the West fears is seeking nuclear arms. Tehran insists its nuclear program is aimed at generating electricity.

Delegations from the group will go to Moscow for talks with Russian officials Wednesday and to Washington on Thursday.

"For the past 18 years, the issue of nonproliferation was neglected," said Mikhail Margelov, chair of the foreign affairs committee in the Russian upper house of parliament.

"Any step forward would be great" for Russian-U.S. relations, because the current level of partnership is "very low," said Margelov.

Richard Burt, a former U.S. arms negotiator, said the group has no firm commitment from governments yet and acknowledged the challenges it faces.

But he said what not long ago sounded like a "radical, unrealistic idea is ... entering the political mainstream."

U.S. President-elect Barack Obama said in July that, "We will make the goal of eliminating all nuclear weapons a central element in our nuclear policy."

U.N. Secretary-General Ban Ki-moon last month urged new negotiations on eliminating nuclear weapons, and French President Nicolas Sarkozy floated an ambitious European disarmament plan Monday.

There are more than 20,000 nuclear weapons in the world's declared nuclear-armed nations: the U.S., Russia, Britain, France, China, India, Pakistan, North Korea. Israel also is widely believed to possess nuclear weapons.

More than 100 political, military, business, religious and civic leaders have lent their support to the campaign, including former U.S. President Jimmy Carter, former Soviet leader Mikhail Gorbachev and former top officials from India and Pakistan. Planners hope to stage a world summit in January 2010.