A Soviet-based radio station has urged Iran to release the hostages held in the U.S. Embassy in Tehran, it was reported yesterday.

The change in the tone of the radio broadcasts, however, was tempered with an accusation by the official news agency Tass that the United States was attempting to put all the blame on Iran in the crisis.

In Madrid, Soviet Foreign Minister Andrei Gromyko called the crisis in Tehran an "internal problem" for Iran.

Tass accused Washington of "growing more rigid" and said that the White House was trying to "put all the responsibility for the current situation on Iran," Washington Post correspondent Kevin Klose reported from Moscow.

However, despite the tendency of the official Moscow media to implicitly assign some of the blame to the United States, a radio station in Soviet Azerbaijan broadcasting to Iran switched Tuesday from encouraging the students that took over the embassy to urging the release of the hostages.

The broadcasts by the "National Voice of Iran" said that freeing the hostages would create "the possibility of ending present tensions and the basis for clarifying our legitimate demands to world opinion."

Two weeks ago, the United States formally protested to Moscow about statements carried by the radio station in support of the militants occupying the embassy.

Washington Post special correspondent Tom Burns reported from Madrid that Gromyko, who wound up a three-day visit to Spain yesterday, was reluctant to discuss Iran.

"We have sought good relations with Iran and the U.S.S.R. has a positive view of the Islamic revolution," he told reporters. "But the situation there is an internal problem and we do not interfere."

Gromyko added that "Soviet policy is that no country should interfere with the affairs of another. I do not want to make comments on the latest developments in the area because I am in Spain and do not have first-hand information."

Spain, for its part, ruled out the use of its bases to facilitate United States military action against Iran, according to Agence-France Presse.

"Spanish bases will never be used to allow one country to act against another," said Information Secretary Joseph Melia.

Israeli Defense Minister Ezer Weizman reportedly said that he believed the hostages' release could not be secured without U.S. military intervention.

Weizman has quoted on Israeli Radio as saying he thought Iran should be given an ultimatum that force would be used if the hostages were not released.

He told Assitant Secretary of State Harold Saunders that the United States was losing all its power and influence in the world, the Radio said, quoting Weizman as asking:

"What point is there in a U.S. aircraft carrier sailing around the Indian Ocean when events like the takeover of the U.S. Embassy in Tehran are happening?"

In its first official comment since the Tehran embassy seizure Nov. 4, the French government also declared that the 49 American hostages should be freed.

France provided Ayatollah Ruhollah Khomeini, now Iran's ruler, with sanctuary for four months after his expulsio from Iraq last year until his dramatic return to Iran in February.

"Whatever the feeling of the Iranian people, no motive can justify the occupation of an embasy and the treatment of its personnel as hostages," a government statement said.

"France appeals to the Iranian authorities to renounce methods which the entire international community can only condemn, and to seek, in ways conforming with international law, the solution of their differences with the United States," the statement said.

The French announcement followed a similar statement Tuesday by the foreign ministers of the European Economic Community meeting in Brussels.

"The ministers reject this violation of international law and call upon the Iranian government to release all the hostages,' the EEC statement said.

In Ottawa, Canadian Prime Minister Joe Clark said his government planned to propose a joint statement by the leading western democracies, supporting the United States in the hostage crisis. He said Canada would contact the United States, Britain, France, West Germany, japan and Italy about the declaration. tThird World nations including Tanzania and Upper Volta also urged Iran to release the hostages. Guyana expressed concern and India said it was giving "due consideration" to a letter sent by President Carter asking for India's assistance in helping to secure the release of the hostages.

An authoritative front-page editorial in the government-owned Tanzanian newspaper, the Daily News, said that Khomeini was losing world sympathy for the Iranian revolution by "this indefensible action against innocent people . . . against the very basis of international diplomatic relations."

President Sangoule Lamizana of Upper Volta, a Moslem, reportedly sent a telegram to Iranian authorities that said the seizure of hostages "reflects poorly on what we know and believe to be the Islamic faith and universally admitted and respected principles in international relations."

In Geneva, the International Commission of Jurists condemned the Iranian threat to put the remaining U.S. hostages on trial as spies and called for their release.

"The suggestion that all or virtually all of the diplomatic staff were engaged in espionage is beyond credence," the commission said in a statement. "But even if there were evidence to support the allegations, there is no right to bring the persons concerned to trial. The only remedy under international law is to expel them from the territory."

It added that "it is to be hoped that reason will prevail and that these hostages will be released forthwith."