The White House said Tuesday that U.S. missile defense plan in Europe would not block the United States and Russia from reaching a new treaty to reduce their nuclear weapon stockpiles.

"The notion that this is in some way an impediment to what is going on with START is not true," White House spokesman Robert Gibbs told reporters, adding that Russian President Dmitry Medvedev had not raised the issue as an obstacle in his recent phone conversation with President Barack Obama.

Early on Tuesday, General Nikolai Makarov, Chief of the Russian Armed Forces General Staff, said U.S. missile defense plan in Europe poses threat to Russia's national defense and has a very negative effect on the talks for a new treaty to replace the Strategic Arms Reduction Treaty (START) that expired on December 5.

On September 17, 2009, President Obama announced the abandoning of the Bush-era controversial missile defense shield program in Eastern Europe, which was viewed as by the Kremlin as a severe threat to Russia's national interests, but unveiled a "phased, adaptive approach" for missile defense in the continent.

The Pentagon claims that the new defense plan, expected to be carried out from 2011 to 2020, would sustain U.S. homeland defense against long-range ballistic missile threats, speed protection of U.S. deployed forces, civilian personnel, and their accompanying families against the near-term missile threat from Iran.

"Our change in architecture for a missile plan that protected Europe and protected this homeland in a better way was announced last September, yet we have had substantive negotiations going on for many months," said Gibbs.

According to the spokesman, negotiators from the two sides are still trying to hammer out the treaty, under which the nuclear warheads each side holds will be reduced to 1,500 to 1,675, while the launchers will be limited to 500 to 1,000.

President Obama and President Medvedev both consider the arms control process as a vital step to boost mutual trust between the two countries, and have vowed to work together to ensure that a new treaty on strategic arms control entering into force at the earliest possible date.

"There's a series of things that whenever you get down to this point in a treaty, you're taking conceptual agreements and putting them into words. And there are going to be some fights over different words, and that's what they're working through," said Gibbs.

"But I can assure you, it's not our different approach to missiles," the spokesman added.