The plan, which Fox News has learned was agreed to in principle during negotiations, would constitute the most intrusive weapons inspection program the U.S. has ever accepted.
Foreign Minister Sergey Lavrov, who met with Secretary of State Hillary Clinton, said publicly Tuesday that the two nations have made "considerable" progress toward reaching agreement on a new strategic arms treaty.
The 1991 Strategic Arms Reduction Treaty, or START, expires in December and negotiators have been racing to reach agreement on a successor.
Clinton said the U.S. would be as transparent as possible.
"We want to ensure that every question that the Russian military or Russian government asks is answered," she said, calling missile defense "another area for deep cooperation between our countries."
On another critical issue, Lavrov declared that it would be counterproductive to threaten Iran with more sanctions over its nuclear program -- as he resisted efforts by Clinton to win agreement for tougher measures should Iran fail to prove its program is peaceful.