FACTBOX: Issues for future U.S./Russia arms deal

(Reuters) - Russian President Dmitry Medvedev and U.S. President Barack Obama will sign a declaration on a new nuclear arms reduction treaty next Wednesday, a Kremlin aide said on Saturday, Russian media reported.

The Strategic Arms Reduction Treaty (START I) is due to expire this December.

Below are some of the key issues surrounding the negotiations for any new agreement.

COUNTING NUCLEAR MISSILES

The anticipated 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.

MISSILE SHIELD

U.S. plans to develop a missile system in Europe may be drawn into the negotiations as Russia argues that it would also affect the strategic balance and weaken its position.

Russian experts such as Vladimir Dvorkin, a retired major general who now heads the Strategic Nuclear Forces Center, said that while both countries want a new treaty this year, many differences may complicate the talks.

He said the main concern from Russia’s perspective is the U.S. plan for a missile defense system, differences between Moscow and Washington over the way warheads are counted and the possible storage, rather than destruction of warheads removed from missiles or other forms of delivery vehicles.

CONVENTIONAL WEAPONS

Russian analysts say of concern to Moscow is a U.S. plan to convert nuclear missiles into conventional weapons. Russia says those weapons should be covered by the new treaty as they could be easily converted back into nuclear weapons.

The United States also wants to deploy conventional warheads on submarine-based missiles, but Russia may object if it believes these could easily be swapped for nuclear warheads.

NEGOTIATIONS

U.S. President Barack Obama has nominated Rose Gottemoeller, a specialist in Russian defense and nuclear issues, to serve as assistant secretary of state for verification and compliance. Gottemoeller, a former director of the Carnegie Moscow Center, will be responsible for the U.S. negotiations but still has to be confirmed in her post.

COSTS OF NUCLEAR WEAPONS

Both countries would benefit from the reduced cost of maintaining a smaller nuclear arsenal and although both sides say they want a deal agreed this year, earlier negotiations on complex arms control treaties have been protracted.