MOSCOW The United States and Russia will begin formal talks on reducing the nuclear weapons stockpiles on Tuesday in Moscow:
Following are some of the key issues:
HOW WOULD THIS ADVANCE PREVIOUS DEALS?
A new deal would replace the 1991 Strategic Arms Reduction Treaty (START I), which led to the largest bilateral reductions of nuclear weapons in history and is due to expire in December.
Russian President Dmitry Medvedev and U.S. President Barack Obama said in April the proposed arms deal would go beyond the 2002 Strategic Offensive Reductions Treaty (SORT), which committed both sides to cutting arsenals to between 1,700 and 2,200 warheads by 2012.
HOW MANY WARHEADS DO BOTH SIDES HAVE?
As of January 1, Russia had 469 deployed intercontinental ballistic missiles (ICBM) while the United States had 550 such missiles, though Russia has more warheads per missile, according to the U.S. State Department.
Russia had a total of 3,909 warheads while the United States had 5,576 warheads, according to the State Department data. The Russian Foreign Ministry has not published its own figures.
WHY DOES A NEW DEAL MATTER?
Russia regards START I as the cornerstone of post-Cold War arms control and believes letting it lapse could upset the strategic balance with the United States.
Both sides regard a new deal as a way to "press the reset button" on relations which were damaged by last year's war in Georgia, differences over a planned U.S. missile shield in Europe and Moscow's opposition to NATO expansion.
An agreement would also help Washington and Moscow to set an example to other countries ahead of talks next year on revising the Non-Proliferation Treaty (NPT).
WHAT ARE THE HARD ISSUES?
The negotiations will focus on how warheads are counted and how they can be deployed on delivery vehicles. For example, if a missile carries 10 independent warheads, does it count as a single weapon or 10? Russia insists on counting all warheads but the United States believes that only those deployed on existing missiles, not those that are in storage, should be counted.
WHAT ABOUT THE U.S. MISSILE SHIELD PLAN?
U.S. plans to develop an anti-missile system in Europe may be drawn into the negotiations because Russia says it undermines national security. Washington says the system is aimed at intercepting missiles from hostile states such as Iran, and is not directed against Moscow.
WHAT HAPPENS NEXT?
Negotiators will report back by July when Obama will travel to Moscow for a summit. Diplomats says this may give political impetus to agreeing a new text by December when START I expires.
(Reporting by Conor Sweeney; Editing by Robert Woodward)