The official Tehran radio in a surprising departure from the harsh views expressed earlier by militant Islamic students, took a conciliatory tone today toward the U.N. Security Council resolution calling for release of the 50 hostages held at the American Embassy.

The unexpectedly mild radio commentary and the absence of any comment from the ruling Revolutionary Council contrasted with the students denunciation of the resolution passed unanimously yesterday as "worthless."

Meanwhile, there were ominous reports from the holy city of Qom that supporters of the country's two most popular religious leaders. Ayatollah Ruhollah Khomeini and his chief rival Ayatollah Kazem Shariatmadari, clashed today, with Shariatmadari's forces claiming one of their number was killed.

The radio commentary pointed out that the Security Council resolution did not condemn Iran but rather asked the United States and Iran to solve their problems peacefully.

"It has also left the way open for continuing activities in the framework of the U.N. Charter and utmost efforts through the secretary general to resolve the differences peacefully." Tehran radio continued.

The conciliatory tone of the radio analysis could mean another split between the governing authorities here and the more radical students, who have won every dispute so far.

But some diplomatic observers here saw it as a hopeful sign that Iran is looking for a way out of what appears to be a complete impasse -- with the students demanding that the United States exchange the deposed shah for the hostages and the American goverment insisting it will not give in to blackmail.

U.N.Secretary General Kurt Waldheim was reported today to have spoken by telephone with Iran's new foreign minister, Sadegh Ghotbzadeh, but there was no information available here on their conversation.

Ghotbzadeh, however, was reported to have visited the students in the U.S.Embassy for an hour this afternoon on the eve of a trip to Qom to see Khomeini on Thursday. While there was no official confirmation of Ghotbzadeh's visit -- he was seen going in the back door of the embassy -- observers here looking for any indication of movement in what now appears to be a static situation saw it as another hopeful sign.

The students, however, have been unbending in their public statements on the U.N.action.

"As far as we are concerned," a student spokesman said from inside the U.S. Embassy, "the U.N. Security Council's opinion is worthless and will not affect us in any way." The students contended that the Security Council is dominated by the United States and the CIA.

One member of the Revolutionary Council, Hajatoleslam Hashemi Rafsanjani, said he believed the resolution has no worth, "If we had considered any value in the United Nations, we would have taken part in the debate," he said.

But the Revolutionary Council itself, which had been expected to issue a statement on the resolution after its meeting tonight, remained silent.

Meanwhile, there were signs of a possible worsening of the feud between Khomeini and Shariatmadari, the head of the Turkish-speaking province of Azerbiajan, where one-third of the Iranian population lives.

Differences between the two are longstanding and now have burst into the open at an especially critical time since some obsrvers believe Khomeini has been whipping up anti-American frenzy to cover internal problems in the country.

According to an aide to Shariatmadari, one of his guards was killed in a shootout today in an alley near Shariatmadari's house. The shooting followed shouts of "Death to Shariatmadari" by supporters of Khomeini during a demonstration near one of Qom's holy shrines.

The two men have been rivals for years, with Khomeini now holding the upper hand but Shariatmadari remaining powerful because of the great support he holds among the national minorities in the northwest corner of Iran. Shariatmadari's latest break with Khomieni came when he opposed parts of the new constitution approved by voters last weekend. The constitution grants sweeping civil powers to the clergy, especially Khomeini.

The question of whether the American hostages wouyld be tried as spies remained unclear tonight. It is certain, though, that the threat of spy trials is being used as a bargaining chip by the students, who have said the trials will start immediately if the shah is allowed to leave the United States.

Ayatollah Mohammed Beheshti, secretary general of the Revolutionary Council, said the trials would be "official" if they are held, and would not be run by the students. Instead, he told reporters, the Americans would be tried by an Islamic court with judges who are experts in Islamic law.

Beheshti said that the charge d'affaires of the U.S. Embassy, Bruce Laingen, who is being held at the Foreign Ministry with two other American diplomats who were away from the embassy at the time of the takeover on No. 4, is not considered a hostage. But, Beheshti said, he cannot leave the Foreign Ministry because the government fears for his safety if he is on the streets.

Beheshti denied that Iran is encouraging Moslems in other countries to demonstrate against the United States. The radical students, however, today called on Saudi Arabian oilworkers to rise up against "this great Satan" (America) who, they said, "plunders your oil and sucks your blood."

"Rising against the U.S. is a godly act, " the students declared in a statement, "and you the Moslems of Arabia carry that burden more than anyone else."

In other news from here, former foreign minister Ibrahim Yazdi warned Iranians "to be on the alert so that after getting rid of the United States we do not fall into the hands of another imperialist such as the Soviet Union."