Updated

WASHINGTON (AP) — The Obama administration warned Congress on Tuesday that failure to ratify a new nuclear arms deal with Russia would weaken the United States.

Defense Secretary Robert Gates assured a Senate committee that the "new START" nuclear reduction and monitoring pact does not prevent the United States from defending itself against missile attacks.

Secretary of State Hillary Rodham Clinton said the deal gives the United States leverage when it argues that other nations should not develop nuclear weapons.

Both officials testified alongside the top U.S. military officer in urging the Senate to quickly ratify the treaty.

The treaty replaces the 1991 START treaty, which expired in December. Passing a new version has been a national security and foreign policy priority for the Obama administration.

The treaty is expected to win ratification, although some Republicans have raised questions about how it will be enforced and whether it leaves the U.S. vulnerable to certain kinds of attack.

A number of senior Republicans have signaled their support for the deal, including Sen. Richard Lugar of Indiana. Lugar told the Senate Foreign Relations Committee that passing up the chance for a strategic nuclear arms control deal with Russia "would be an extremely precarious strategy."

The Senate committee is the first step toward what the administration hopes will be ratification by the end of the year.

President Barack Obama and Russian President Dmitry Medvedev signed the treaty last month, but it cannot take effect until it is endorsed by the two nations' legislatures.

Administration officials assured Congress that the treaty would not limit the U.S. ability to develop missile defense systems.

Gates told the Senate committee the treaty also will allow the U.S. to develop the ability to strike a target anywhere in the world in less than an hour using a conventional weapon. Russia has signaled its strong opposition to U.S. proposals to place conventional warheads on strategic missiles.