WASHINGTON — Soviet leader Mikhail S. Gorbachev, who arrives here today for his third summit with President Reagan, is prepared to discuss withdrawing Soviet troops from Afghanistan and scaling back the Soviets' strong advantage in non-nuclear forces in Europe, Soviet officials said Sunday.
Although Gorbachev's three days of meetings with Reagan will be dominated by nuclear arms control, U.S. officials expect the two leaders also to discuss other issues that aggravate superpower relations.
Warn Against Optimism
But some U.S. officials, contending that the pro-Soviet regime in Afghanistan could not last three months if the Soviets ended their eight-year occupation, warn against optimism on an early Soviet withdrawal. And on the issue of non-nuclear forces in Europe, Secretary of State George P. Shultz said Western Europe would have to be a party to any agreement to reduce the conventional forces of NATO and the Warsaw Pact.
Reagan and Gorbachev, who will hold four one-on-one meetings and a private lunch during the summit, plan to complete work Tuesday on the centerpiece of the event, signing the treaty that will eliminate both nations' medium-range nuclear missiles. They then will work toward a second treaty that would cut in half the much more potent long-range nuclear arsenals of the superpowers.
Sends New Signals
Gorbachev, portrayed by many American officials as especially eager to reach an agreement on strategic arms, on Sunday sent new signals that Reagan's space-based missile defense system, the Strategic Defense Initiative (SDI), may no longer be considered an obstacle to such a treaty. Soviet officials said in interviews that SDI is not even an issue for the summit, although it was cited by Gorbachev as a chief stumbling block when his last meeting with Reagan collapsed 14 months ago in Reykjavik, Iceland.
At the same time, Gennady I. Gerasimov, the spokesman for the Soviet Foreign Ministry, said on ABC-TV's "This Week with David Brinkley" that Gorbachev has put a proposal to withdraw Soviet troops from Afghanistan "very high" on the summit agenda.
Gerasimov pointed out that Reagan himself had noted in a televised interview last week that the military occupation was something Gorbachev inherited when he took office nearly three years ago, and he said "we're trying our best" to resolve the issue.
However, U.S. officials said the Soviets apparently have not determined a way to withdraw soon--as the United States is demanding--without allowing the U.S.-backed rebels to overrun government forces and seize control.
On the subject of the Soviets' substantial superiority in conventional, non-nuclear forces in Europe, Gerasimov said that the Soviets can accept the principle of asymmetric reductions, or Soviet troop cutbacks exceeding those by the Western allies, to achieve an agreement.
Shultz, also interviewed on the Brinkley program, said the United States also will be seeking agreements on conventional forces and chemical weapons while working on the strategic arms issue.
Any agreement that called for a mutual reduction of conventional forces in Europe, Shultz said, would require consultations with North Atlantic Treaty Organization allies, because "we're talking about NATO forces. And most of the NATO forces are not U.S., and I think . . . everybody will be very slow to talk about reductions of U.S. forces." NATO, he said, is formulating a position on the issue.
A government specialist in Soviet affairs told The Times that he expects the Soviets to eventually announce "a very major" proposal for reducing conventional forces, but he doubts Gorbachev will push such a proposal at the summit.
Gorbachev is more likely to find a European setting for such an announcement and to time it so that it might aid Reagan in his campaign to win Senate ratification of the intermediate-range missile treaty, the specialist said. Opponents of the treaty cite the Soviets' superiority in conventional forces as a major reason for their opposition.
No Push on SDI, U.S. Hopes
U.S. officials said they hope Soviet officials do not try to push for limits on SDI at the summit, because Reagan will not accept them.
Howard H. Baker Jr., the White House chief of staff, predicted that Gorbachev, in his discussions with Reagan, will seek progress on strategic weapons cuts, "perhaps without requiring as a precondition that the President abandon SDI or reduce SDI or postpone SDI, which he's not going to do."
Reagan is "pressure proof" on that issue, Baker said.
Georgy A. Arbatov, the Soviets' leading specialist on American affairs, said his government, leaving SDI aside, is "ready to make deep cuts in strategic weapons if both sides adhere to the ABM treaty."
Although there are differing interpretations of some provisions of the 1972 Anti-Ballistic Missile Treaty, it clearly forbids deployment of missile defenses except around one site in each of the two countries. It does not prohibit research, however.
Push for START Agreement