Bush Prods Kremlin on Arms Talks : Summit: He asks Gorbachev to push for a nuclear weapons pact soon. The President would like the two to sign it at an end-of-July meeting.

WASHINGTON —  President Bush said Saturday that he has personally urged Soviet President Mikhail S. Gorbachev to iron out remaining U.S.-Soviet differences on arms control before their July 17 meeting in London so the two sides can sign an arms reduction accord by the end of this month.

Speaking to reporters while playing golf in Maryland, Bush indicated that his message--delivered orally by Jack F. Matlock Jr., the U.S. ambassador in Moscow--is designed to prod Gorbachev to push his own negotiators for more progress before the London meeting.

“I want to get their team moving forward as fast as ours is,” the President said, “and what I want to do is be sure that (Gorbachev) energizes his bureaucracy just as we’ve energized ours--and his military particularly.”

Bush added that he still wants to complete a treaty on limiting long-range nuclear weapons in time to hold a full-fledged U.S.-Soviet summit by the end of July, as he has indicated before.

“He (Gorbachev) knows and we know that to get a summit agreement, that must be finished up. . . ,” the President said. “What we’re doing is trying to move that process forward once again.”

Bush has used such personal appeals before in an attempt to score a breakthrough on a diplomatic stalemate just before he is scheduled to meet personally with another head of government, and Saturday’s move appeared to be just such an effort.

Analysts said the fact that the message was delivered orally rather than in a formal letter suggested that it was intended mainly to provide more political impetus rather than to resolve the highly technical details of the remaining issues.

However, diplomatic observers pointed out that Bush’s remark that the treaty must be completed before the United States will agree to hold a U.S.-Soviet summit marked a slight hardening of the U.S. position on that issue. Previously, Bush has been less specific.

The United States and the Soviet Union have been negotiating a strategic arms reduction treaty--known by its acronym, START--for almost 10 years now, and are said to be virtually in full accord except for a few technical details.

Partly because of this snag, the two have postponed a separate U.S.-Soviet summit meeting that Bush and Gorbachev were expected to have held in Moscow this month to sign the treaty and explore other bilateral initiatives.

High-level negotiators from both sides met again last week in an attempt to work out remaining differences but apparently were unable to break the impasse. Undersecretary of State Reginald Bartholomew emerged from the session with little to say.

Gorbachev has been eager to complete the arms-control treaty, in part to make an impression on the leaders of the world’s seven major industrialized democracies whom he will address in London next week. Gorbachev is expected to ask in his speech to the leaders of the so-called Group of Seven for massive economic aid from the West--a request Bush has treated lukewarmly, saying Moscow first must make needed economic reforms.

Some analysts say that a breakthrough on START would intensify pressure on the industrial democracies to be more generous. Besides the United States, the Group of Seven includes Germany, Japan, Britain, France, Italy and Canada.

U.S. officials say privately that it is almost certain the arms-control issue will come up during a two-hour lunch that Bush and Gorbachev have scheduled after the formal conclusion of the Group of Seven summit July 17, implying that a deal could be announced then if the two men see eye to eye.

Gorbachev is scheduled to address the leaders of all seven democracies after he has lunch with Bush.

Bush and Gorbachev have exchanged messages frequently on the arms control issue, often on relatively technical matters.

U.S. officials have cited several issues as stumbling-blocks that remain in the push for a treaty--among them the amount of information that can be obtained from Soviet missile tests, and how much leeway to allow for “modernizing” old missiles to make them more powerful.

But officials say the most crucial difference between the two sides is over the issue of “downloading”--that is, whether to allow Moscow to meet treaty limitations on the number of warheads that a missile may carry merely by removing some of those that the missiles now carry at full capacity.

U.S. strategists caution that if Moscow were allowed to pursue such a path, the Soviets could easily, in the event of an armed confrontation, restore absent warheads to the empty but still usable slots from which they were removed--effectively circumventing the purpose of the arms-reduction treaty.

Bush Administration officials fear that unless that loophole is plugged, Congress may prove unwilling to ratify START, and the negotiators will be forced to go back into negotiations again.

U.S. officials say that if the treaty isn’t completed by the end of July, it is unlikely to be finished until mid-autumn.

Top Administration officials indicated Saturday that they are becoming increasingly apprehensive that the present stalemate would not be broken this month, partly because the Soviet military has been taking a much harder line in the talks than had been anticipated.

Secretary of State James A. Baker III said Saturday that the President had urged Gorbachev “to send his people with instructions so we can close out START. . . .”

“They know what the issues are,” Baker said. He added that Bush’s message was intended to convey the idea “that we’re getting short on time if we’re going to have a summit by the end of July.”

The President said his message was “strictly to express once again our continued interest in getting this (arms reduction) agreement finished” and to make sure that Gorbachev “energizes his bureaucracy” so that some progress can be made.

Times staff writers Doyle McManus and Robert C. Toth contributed to this report.