In a new blow to the Iranian government, the president of the Regency Council appointed to reign in the shah's absence resigned today before calling on Ayatollah Ruhollah Khomeini, the chief of the religious opposition.

While the resignation by Sayed Jalaleddin Tehrani seemed puzzling in some aspects, it clearly was a major victory for Khomeini. His followers at their headquarters in the Paris region cheered the announcement.

The Regency Council carries broad importance as the symbol of Shah Mohammad Reza Pahlavi's continued claim on power in Iran. The monarch has insisted his departure a week ago was only for a prolonged vacation, although most observers have called it indefinite and perhaps permanent exile.

Khomeini had declared he would receive Tehrani, who arrived here from Iran on Thursday, only if he resigned and declared the Regency Council to be illegal. A spokesman for Tehrani and one of Khomeini's aides declared publicly that Tehrani had complied, but Tehrani himself refused to say that he considered the council illegal in a confused telephone interview.

During a telephone call to Tehrani, an Iranian doctor insisted on speaking on his behalf and would only put the aged Iranian politician on after some insistence.

Tehrani, 81, came on the phone and started answering questions in a way that contrasted with the doctor's hardline anti-shah statements. Then the doctor came back on the line and said, "Mr. Tehrani is very tired. He cannot speak any longer."

The doctor, Saseifeddine Nabavi, is president of the Iranian Cardiologist Association. He claims to be the personal physician of Khomeini, who is 78, and he said he served as the intermediary between the two.

Earlier today, Tehrani told The Associated Press that he had resigned for purely personal reasons.

Speaking after his meeting with Khomeini this afternoon, Tehrani said that following his departure from Tehran on Thursday, "public opinion became very overheated, so I decided to resign.... I thought I should abandon my functions after the demonstrations."

He said public opinion had made Khomeini "a leader of reputation," so "we should respect it." But Tehrani refused to say there had been anything illegal about the shah's government or the Regency Council.

The president said he had resigned because of his own view of the situation but that it was for the other members of the Council to make up their own minds.

Nabavi quoted Tehrani as saying he was resigning, among other reasons, "because I am a follower of Khomeini." The doctor insisted that Tehrani is in vigorous health and in full command of himself.

Tehrani is a veteran politician who has served the shah's government in a number of capacities. He has a residence near Paris and apparently intends to stay there for some time.

Former U.S. attorney general Ramsey Clark met with Khomeini earlier in the day, apparently the first contact between Khomeini and an American political figure in a position to report to the U.S. government.

Clark came to Paris from Tehran, where he had contacts with U.S. Ambassador William Sullivan. But Clark did not get in touch with the U.S. Embassy here and went directly to the airport to fly to New York after meeting with Khomeini.

U.S. officials here indicated that they presume Clark will communicate with the Carter administration at home but his visit to Iran and Paris was described as private.

Clark was accompanied by Richard Falk of Princeton University, an international affairs specialist. Clark told reporters they had called on Khomeini "as individual American citizens concerned about American policy toward Iran."

Clark was prominent in the movement against the Vietnam war and traveled to Hanoi during the war to check on reports of U.S. bombings of civilian targets.

He said after seeing Khomeini for about half an hour that he was "deeply impressed by the nature and depth and purpose of the movement in Iran that has established the opportunity for a new freedom," adding: "We have the highest hopes that it will achieve social justice."