The Soviet Union, Japan and even landlocked Switzerland will be among the challengers for the 1992 America's Cup, the San Diego Yacht Club announced after a deadline for entries passed.

Twenty yacht clubs from 15 nations will race the new America's Cup class of 70-foot monohull yachts in May 1992 off San Diego Bay. That is a record number of clubs and of challenging syndicates.

"As impressive as the total number of challengers is, the more significant number may be the 15 countries involved," said Tom Ehman, executive vice president and general manager of the 1992 America's Cup.

Ehman said nine countries will be racing for the first time: Denmark, Scotland, West Germany, Japan, Switzerland, the Soviet Union, Spain, Yugoslavia and Sweden. He said that is more than the total number of challengers who competed at Fremantle, Australia, in 1987.

Cup veterans challenging again this time are Australia, England, France, Italy, Canada and New Zealand.

New Zealand's Michael Fay, whose 1988 renegade challenge ended in failure in the New York Court of Appeals just last month, again represents the Mercury Bay Boating Club.

Ehman said there are other firsts this time around.

Japan is the first Asian country to be involved in the America's Cup. The Soviet Union and Yugoslavia bring in Eastern Europe for the first time. Spain's entry will represent the Spanish-speaking world for the first time, exactly 500 years after Columbus's 1492 voyage to the New World.

Ehman said a second Soviet challenge had been received from the Leningrad Yacht Club requesting 14 more days to come up with the $25,000 fee. The Odessa Arcadia Racing Yacht Club is the other Soviet entry.

The San Diego Yacht Club has agreed to the Leningrad request but final word must come from the challengers. They will be meeting in San Diego to decide Thursday their Challenger of Record -- the syndicate charged with organizing the challenger sail-offs.