MOSCOW, Russia (CNN) -- Russian and U.S officials are meeting Wednesday and Thursday in Moscow to discuss a replacement pact for the Strategic Arms Reduction Treaty I, which is expiring in December.
Russian President Dmitry Medvedev and President Obama met in London in April.
"The key thing is that our two countries seem to have decided that we do want to pursue very intensive negotiations between now and December 2009 to try to achieve a new treaty to replace START when it goes out of force December 5," said Rose Gottemoeller, the U.S. assistant secretary of state. "That is actually a key point of agreement between Moscow and Washington."
Gottemoeller is participating in talks in Moscow with Anatoly Antonov, the director of the Russian foreign ministry's Security and Disarmament Department.
"These talks are not just an exchange of opinions but a switch to a detailed discussion of the future treaty," Antonov said, hinting at the summer meeting in Moscow between President Obama and Russia's President Dmitry Medvedev.
Since the signing of START I in July 1991, countries such as India and Pakistan have obtained nuclear weapons. However, that has not undermined the importance of a new treaty between Russia and the United States, officials say.
"Russia and the United States, with 90 percent of the world's nuclear weapons, bear primary responsibility for reinvigorating the strained nonproliferation regime," Russia's foreign minister, Sergey Lavrov, said on the ministry's Web site. "They must make deeper cuts in their arsenals, reinforce [International Atomic Energy Agency] safeguards and encourage universal adoption of the additional protocol."
Obama held a meeting in the Oval Office on Tuesday to discuss U.S. nonproliferation policy with former Secretaries of State Henry Kissinger and George Schultz, former Defense Secretary William Perry and former Sen. Sam Nunn of Georgia.
It is "imperative" to "reduce and ultimately eliminate" the risk posed by nuclear weapons at a time when organizations like al Qaeda are seeking fissile material and countries like Iran and North Korea are trying to acquire a nuclear capability, Obama said.
"One of the things I have always believed strongly is that both the United States and Russia and other nuclear powers will be in a much stronger position to strengthen what has become a somewhat fragile threadbare nonproliferation treaty if we are leading by example and if we can take serious steps to reduce the nuclear arsenal," Obama said at an April 1 news conference.
As of January 1, Russia had 814 deployed carriers of nuclear arms, including ground-based intercontinental ballistic missiles, submarine-launched ballistic missiles and heavy bombers, as well as 3,909 nuclear warheads, according to a U.S. State Department report published in April.
"It would meet the interests of this country if the new treaty restricted the number of carriers of strategic nuclear weapons, not just warheads, and extended the ban on deploying strategic offensive armaments outside of national territory," said Col. Gen. Nikolai Solovtsov, commander of the Strategic Rocket Force.
"Not a single launcher or missile regiment will be decommissioned if their service life has not run out. Such an approach will remain with regard to the new treaty that will be signed with the United States," Solovtsov said.
The same report said the United States had 1,198 carriers and 5,576 warheads.
Both countries are close in the total number of intercontinental ballistic missiles: 550 in the United States and 469 in Russia. However, Russian missiles had more warheads: 2,005, compared with 1,250 in the United States.
The United States is superior in the number of strategic bombers: 216 compared with 77 in Russia. It also has more warheads on these carriers: 4,326 against 1,904.
The current treaty binds Russia and the United States to reduce the number of deployed carriers to no more than 1,600 and the number of warheads to no more than 6,000.
Obama and Medvedev are scheduled to meet from July 6 to July 8 in Moscow.