WASHINGTON -- The United States and Soviet Union ended four days of intense negotiations yesterday with a single complicated issue still blocking a landmark treaty to slash long-range nuclear weapons.
Secretary of State James A. Baker III said experts would continue to work on the final sticking point -- which involves what new types of missiles would be allowed under the treaty -- in hopes that he and his Soviet counterpart could renew their efforts to reach agreement while both are in London this week.
But he voiced little optimism. He left the date for a superpower summit -- which the United States has made contingent on reaching a strategic arms agreement -- in the air.
President Bush, at a joint news conference earlier in the day with French President Francois Mitterrand, said, "We are not going to make a deal to just try and get something done before Wednesday, and nor are the Soviets."
Soviet Foreign Minister Alexander A. Bessmertnykh, along with the chief of the Soviet General Staff, arrived in the middle of last week for what was hoped would be the final stage of nearly 10 years of negotiations on a treaty limiting each side's arsenal of the most threatening missiles, bombers and submarines.
In the course of talks that were extended twice, the two sides cleared up two of the three remaining issues blocking the pact. They deal with cutting the number of warheads per missile, allowing more missiles under treaty limits and sharing data emitted from missile test flights.
"While we were unable to conclude this one final issue, we have made what I would characterize as outstanding progress toward completion of a START agreement," Mr. Baker said, using the acronym for Strategic Arms Reduction Talks.
Mr. Bessmertnykh, joining Mr. Baker for a brief news conference before returning to Moscow, said that the two delegations had made "a tremendous effort" and that he was "very much satisfied" with the result.
"The Washington stage of the negotiations is probably one of the most productive talks on the START treaty held at the ministerial level," he said.
The problem remaining involves just a piece of the puzzle on what types of new missiles could be introduced by either side under the treaty.
The United States wants to curb Soviet capability to introduce new types of missiles that closely resemble its existing stockpile. Washington therefore had demanded a substantial change in "throw weight" -- a missile's lifting power or payload capacity -- before a missile could be considered in the "new type" category.
The two sides settled on a changeof 21 percent but failed to
determine how throw weight would be defined, Mr. Baker said.
"When you apply a percentage to throw weight, you've got to know how you define throw weight for that purpose," he said.
"If we can cover this one last issue, we will have an agreement."
Both sides have adopted the position that the whole treaty is unsettled until every element is resolved.
But Mr. Baker said Geneva negotiators would spell out the "elements of common ground" reached in Washington so that they can be considered solved and not require any further negotiation.
The overall treaty, the first ever to cut nuclear weapons that the superpowers aim at one other, would cut the Soviet warhead arsenal from 11,000 to 7,000 and the U.S. arsenal from 12,000 to between 8,000 and 9,000.