WASHINGTON?Less than a week before their summit, President Bush and President Vladimir Putin are moving closer to an understanding that would meet Russia’s desires for deep cuts in nuclear arsenals and give the United States more leeway to test missile defenses.

Two-thirds of the American nuclear arsenal would be consigned to the scrap heap, a senior U.S. official said Thursday. Russia has said it wants to do the same as well with its storehouse of long range warheads.

Even if there is no formal accord, Bush intends to get rid of hundreds of weapons the U.S. Joint Chiefs of Staff have concluded are superfluous, said Condoleezza Rice, the president’s national security adviser.

Based on the Pentagon review, Bush has concluded how many warheads the United States should retain, and Putin has taken a more agreeable stance on a U.S. anti-missile defense.