US and Russian defense officials began two days of talks here Tuesday on nuclear weapons cuts and other security issues following a US strategy review that calls for storing rather than destroying decommissioned warheads.

“They have begun,” said Marine Lieutenant Colonel Michael Humm, a Pentagon spokesman. “They will be having strategic force reduction conversations.”

The talks come only a week after the Pentagon unveiled a plan to reduce the US strategic nuclear arsenal from 6,000 warheads to 3,800 by 2007 and to as low as 1,700 warheads over the next 10 years.

Russia also has urged cuts in US and Russian nuclear arsenals to 1,500 warheads each.

But sharp differences remain in US and Russian approaches to nuclear arms reductions with Washington seeking to preserve the capacity to rapidly rebuild its nuclear forces if conditions change.

As a hedge, the United States wants to keep decommissioned warheads in its active stockpile rather than destroy them, Pentagon officials have said.

It also wants to strengthen its nuclear weapons production infrastructure and shorten the time in which the United States could resume nuclear testing if called upon to do so by the president.

The Russian foreign ministry said last week that any cuts in nuclear forces should be irreversible.

In Moscow, Russian officials said the talks will begin a process aimed at coming up with a legally binding document by mid-year that sets forth the parameters of the nuclear arms reductions and verification measures.

The document would ensure “the transparency of the deactivation and storage of these missiles,” said Valery Manilov, an aide to deputy chief of staff General Yury Baluyevsky, the head of the Russian delegation.

The US delegation is led by Douglas Feith, undersecretary of defense for policy.

While Moscow wants the cuts to be formalized in a binding agreement, Washington insists it is prepared to make cuts unilaterally and there is no need for detailed arms control negotiations.

However, the two sides have agreed to talks aimed at ensuring predictability and accountability in making the cuts.

The US intelligence community concluded in a report published last week that unless Moscow significantly increases funding for its strategic forces, Russia’s arsenal will decline to less than 2,000 warheads by 2015 — with or without arms control.

Missile defense issues also are expected to be discussed in the talks here, along with counter-terrorism cooperation, biological weapons and counter-proliferation, and military-to-military activities.

President George W. Bush announced last month that the United States will withdraw from the 1972 ABM treaty in six months to pursue missile defense projects free from the constraints imposed by the treaty.

Russian President Vladimir Putin has said scrapping the ABM treaty was a mistake but so far has avoided a confrontation with Washington in favor of talks aimed at redefining their strategic relations.