LOS ANGELES--President Reagan, in a major address setting the tone for U.S.-Soviet talks next week, said yesterday there is no excuse for the way U.S. security was handled at the Moscow Embassy, but added that the spy scandal should not derail arms control negotiations or relations between the superpowers.

"If I had to characterize U.S.-Soviet relations in one word it would be this--'proceeding'," Reagan said in remarks prepared for delivery to the World Affairs Council. "No great cause for excitement, no great cause for alarm."

The President offered no major new proposals in his address. But he started off by denouncing the Soviets for infiltrating the embassy. At the same time, he was critical of the way U.S. officials oversaw security at the facility.

"There's no excuse for what the Soviets did or for the way security was handled in Moscow," Reagan said, adding, "Such Soviet actions come as no surprise."

Reagan's criticism of the manner in which security was handled at the embassy was the strongest yet.

One White House official, who spoke on the condition that he not be identified, said the President clearly intended to fault, U.S. personnel for the security breakdown at the Moscow embassy.

The President said U.S. Soviet relations must be based "not on false hopes or wishful thinking... It's based on a candid assessment of Soviet actions and long term understanding of their intentions."

On the issue of arms control, Reagan said the Soviets have shown "new seriousness" in recent weeks, particularly in the area of eliminating medium range weapons from Europe and cutting back range strategic missiles.

But Reagan also accused the Soviets of attempting his space-based Strategic Defense Initiative. Reagan said he has "made some very forthcoming proposals about not deploying strategic defense for a period of we and the Soviet negotiate."

Another arms control sticking point, Reagan said, was the issue of checking on cheating. Verification remains a critical problem because of the proof record of Soviet compliance with previous agreements, Reagan said.

He also took a strong stand on the linkage between talks on long-range and short-range weapons in Europe.

"We cannot permit the benefit of medium-range weapons from Europe the reduction in longer-range INF [Intermediate Nuclear Force] missiles, for example, to be undermined or circumvented by continuing imbalance in shorter-range INF, missiles, in which the Soviets have an advantage," Reagan said.

Reagan pledged to work closely with the European allies on this point, because they are worried about the Soviets' preponderance of short-range weapons and conventional forces.

In his speech, the President also repeated his request that Soviet leader Mikhail Gorbachev come to the United States. "My invitation to Mr. Gorbachev to come to America still stands. The welcome mat is still out," Reagan said.