Soviet leader Mikhail Gorbachev, assailing U.S. actions against Libya as "an encroachment," today proposed the withdrawal of all Soviet and American military fleets from the Mediterranean, according to the official Soviet news agency Tass.

Gorbachev pledged that the Soviet Union would remove its naval fleet from the Mediterranean region at the same time the U.S. 6th Fleet pulled out, according to Tass.

The sole purpose of the permanent naval presence there, the Soviet leader said, is to counterbalance the 6th Fleet, which threatens "the security of the U.S.S.R., its allies and friends in the immediate proximity of its borders."

Moscow is prepared, "without delay," to enter talks on this issue, he added.

Gorbachev made the remarks in a Kremlin dinner speech in honor of visiting Algerian President Chadli Bendjedid, who arrived here yesterday.

In Washington, the State Department dismissed Gorbachev's offer. "We have briefed the Soviet Union as to why we are there," spokesman Charles Redman said. "That's well understood."

In addition to the U.S.-Soviet naval withdrawal, Gorbachev proposed a regional Mediterranean conference and a "world congress" on questions of foreign debt and other international economic issues.

In his first public statement about the U.S.-Libyan clashes, Gorbachev said: "We resolutely denounce the anti-Libya actions of the U.S.A."

The American action against Libya, he said, is a "punitive operation."

He also accused the United States of mounting a campaign that includes "provocative and threatening" naval maneuvers, "a trade, financial and technical blockade" and "psychological and propaganda warfare."