The presidents of Russia and the United States will meet in Prague to sign a new nuclear arms reduction treaty on April 8, the White House and Kremlin said on Friday.
The two largest nuclear powers have been formally negotiating on a successor to the 1991 Strategic Arms Reduction Treaty (START I) since April 2009.
* WHAT IS THE NEW TREATY?
- Presidents Barack Obama and Dmitry Medvedev said last April that they wanted to agree a new deal by the December 5 expiry date of START I but talks snagged and the two sides agreed to act in the spirit of START until a replacement was ready.
The two leaders agreed in July that a new treaty would limit operationally deployed nuclear warheads to 1,500-1,675, and both sides said on Friday that the specific limit would be 1,550 -- down from current levels of 2,200-2,700.
In the 2002 Strategic Offensive Reductions Treaty (SORT), also known as the Moscow Treaty, each side agreed to cut strategic nuclear warheads to 1,700-2,200 by 2012.
Obama and Medvedev said the limit for delivery vehicles -- the missiles, bombers and systems that deliver a warhead to a target -- should be in the 500-1,100 range. Negotiators agreed on a specific limit of 800, half the 1,600 set in START I.
* WHY IS THE AGREEMENT IMPORTANT?
-- The quest for a START successor pact is a key part of efforts to "reset" relations after increasing tension that peaked with Russia's 2008 war against U.S.-supported Georgia.
Obama has said improving ties with Russia, a key player in Iran and an important source of support on Afghanistan, is a priority.
-- Both the United States and Russia, which hold 95 percent of the world's nuclear arms, say further reductions in their arsenals will improve mutual trust and send a strong signal to other nations at a time when global powers are trying to rein in the nuclear ambitions of Iran and North Korea.
-- The agreement could help create the momentum for a nuclear security summit Obama is hosting in mid-April and a May conference to review the 1970 nuclear Non-Proliferation Treaty.
-- For Russia, its vast store of Soviet-era nuclear weapons is one of the factors keeping Moscow at the top table of world politics.
After Russia's conventional forces were starved of cash in the chaos that followed the 1991 Soviet collapse, its still mighty nuclear deterrent is the centerpiece of the Kremlin's military doctrine.
-- Both sides said the new deal will include detailed verification procedures that were absent from the 2002 Moscow Treaty -- an omission cited by arms experts as a major flaw However, the verification procedures will not be as onerous as in START I.
Verification procedures such as inspections and access to data about missile tests is important because it helps the former Cold War foes accurately to predict how many weapons each side has and thus reduces the chance of a new arms race.
-- A replacement for START I is seen as the first step toward much deeper cuts. Both sides hope an agreement on START could lay the ground for more ambitious talks about reducing the silos of thousands of non-deployed nuclear warheads and shorter-range tactical nuclear warheads.
Those talks could also impose must bigger cuts to deployed strategic warheads and delivery systems.
* WHY DID THE TALKS TAKE LONGER THAN HOPED?
-- The two sides agreed on a news blackout from negotiations in Geneva, so there were few details about what caused the delay in achieving a deal.
-- Russian Prime Minister Vladimir Putin said in December that U.S. plans for a missile defense system were the main obstacle to reaching a new deal, suggesting Moscow wanted it to limit missile defenses.
Obama and Medvedev agreed in July that the treaty will contain a provision describing the relationship between offensive and defensive weapons, but the United States says the pact is not the place for details on missile defense.
-- Remarks about the treaty from both sides on Friday suggested that it will not place specific limits on missile defense. But Russian Foreign Minister Sergei Lavrov said either side has the right to stop reducing strategic offensive weapons if the other side increases its capacity for defense against those missiles.
-- Negotiations over verification measures were said to have been intense. Russia has called for more relaxed procedures than in START I.
That is in part because while Russia has been developing new nuclear missiles to take the place of aging models, the United States is relying mostly on models that will be in service for years to come, prompting Russia to contend that it is getting little new information from verification measures.
(Writing by Guy Faulconbridge and Steve Gutterman in Moscow)