"With this agreement, the United States and Russia -- the two largest nuclear powers in the world -- also send a clear signal that we intend to lead. By upholding our own commitments under the Nuclear Non-Proliferation treaty, we strengthen our global efforts to stop the spread of these weapons, and to ensure that other nations meet their own responsibilities," said Obama.

Experts here said that the new treaty could offer the Obama administration "morality and justice" to push other countries, including Iran and the Democratic People's Republic of Korea, to disarm under the Nuclear Non-proliferation Treaty framework.

Stephen Sestanovich, senior fellow of the Council on Foreign Relations, said that the administration wants the new treaty to establish their "bona fides" at two upcoming multilateral forums: the Nuclear Security Summit in Washington in April, and the Nuclear Non-proliferation Treaty Review Conference in New York in May.

At the press conference with President Obama, Secretary of State Hillary Rodham Clinton said the new START has demonstrated common commitment by Washington and Moscow to making progress toward disarmament under the Nuclear Non-proliferation Treaty.

"One of our top priorities is to strengthen the global non- proliferation regime and keep nuclear materials out of the wrong hands," she said.

Ratification remains unclear

The new treaty, however, has to be passed by U.S. and Russian lawmakers before entering into force. President Obama has to make at least 67 senators support the nuclear arms control deal with Russia in order that it could be passed in the 100-seat Senate.

Early on Friday, the president urged U.S. Senate to ratify the treaty as soon as possible after it is signed. "My Administration will be consulting Senators from both parties as we prepare for what I hope will be strong, bipartisan support to ratify the new START treaty," he said.

John Kerry, chairman of the Senate Foreign Relations Committee, said in a statement that as soon as President Obama sends the agreement to the Senate, his committee "will appeal to all our colleagues to set aside preconceptions and partisanship and consider the treaty on its merits."

"We can't squander this opportunity to reset both our relations with Russia and our role as the world leader on nuclear nonproliferation. This is a major commitment by both countries to reduce their nuclear arsenals and an important step in solidifying our relationship with Russia. Let's get it done," said Kerry.

However, President Obama's allies in the Senate control 59 seats, including 57 Democrats and two Independents. That means Republican's attitude will be vital for the ratification.

"Republicans who want to undermine the administration's case will probe the negotiating record for hidden commitments. In exchange for their votes some will try to exact pledges to accelerate defensive programs," said Sestanovich.