Iranian authorities tonight announced the arrest of the former deputy prime minister of the revolutionary government as a result of documents found in the occupied American Embassy here that purportedly said he cooperated with U.S. diplomats in an effort to improve U.S.-Iranian relations.

According to a television broadcast, Abbas Amir-Entazam was arrested after he arrived here from Stockholm, where he is posted as Iran's ambassador to the Scandinavian nations.

He is the first major official of the revolutionary government, which took power less than a year ago after the overthrow of the shah, to be arrested on charges related to spying or anti-revolutionary activities.

Entazam had been deputy prime minister and the official spokesman for the government of former prime minister Mehdi Bazargan until late this summer, when he received his diplomatic appointment.

According to Iranian Authorities, the seized U.S. documents indicated that he told American officials he hoped to be assigned as ambassador to the United States.

The Bazargan government fell last month over the issue of the 50 American hostages being held in the U.S. Embassy here, which was occupied Nov. 4 by militant Moslem students.

Last week, the Foreign Ministry announced that Iran's ambassadors to Great Britain, West Germany, and the scandinavian states were being recalled to Tehran for consultations.

At that time, diplomats here speculated that the recall of the envoys from West Germany and Great Britain was connected with Secretary of State Cyrus Vance's tour of Europe to get support for possible American sanctions against Iran over the holding of the hostages. But they were puzzled by the recall of ambassadors from Scandinavia.

According to tonight's broadcast, the students who seized the embassy 46 days ago discovered cables and letters referring to Entazam's contact with U.S. diplomats.

A cable from U.S. charge d'affaires Bruce Laingen reportedly said that Entazam "is actually interested in continuing contacts with the U.S. and sincerely trying to settle mutual relations between Iran and the United States" even after he leaves here to become an ambassador.

"Entazam was hopeful," the cable continued, "that his trip to Sweden would not cause a halt in his duty of acting as a communications channel between the United States and Iran. He said he could talk easier in Stockholm than he could in Tehran because there would be no eyes and ears there."

The document most damaging to Entazam was one the students said was a cable from the CIA here to Stockholm saying that the United States was ready to exchange information with him after Sept. 10.

The kinds of contactsf that Entazam was quoted in U.S. documents as wanting are considered normal between diplomats and government officials, and appear on the surface not to indicate espionage on the part of the United States or any attempt by Entazam to sell out his government.

Nonetheless, the current atmosphere her places blame on the CIA and United States for almost everything that goes wrong in Iran -- including inducing Iraq, with which the United States does not have diplomatic relations and which has been feuding with Iran for over a decade, to launch raids into his country.

Another Iranian political figure, Rahmatollah Moghaddm-Maraghei, leader of a party favoring greater self-rule for the province of Azabaijan, was charged by revolutionary prosecutors on the basis of documents found in the U.S. Embassy.

As in the Entazam case, these documents said that Maghaddm-Maraghei was talking to American diplomats about ways to improve U.S-Iranian relations. One of his suggestions was for the United States continue to press for a meeting with Ayatollah Ruhollah Khomeini, the country's revolutionary leader, and send private citizens sympathetic to the revolution on visits here.

Earlier today, Khomeini continued his attacks on President Carter, accusing him this time of acting "like a scared lion" in threatening a naval blockade or other military action against Iran.

Meanwhile, sources here reported that Iranian authorities are seeking an international group of clergymen to come to Tehran to hold Christmas Eve services in the embassy for the hostages. The clergy would also act as international observers to determine the health of the hostages.

This morning, hundreds of thousands of Iranians mixed anti-American slogans with religious prayers for the dead as they paid tribute to Dr. Mohammad Mofatteh, a close associate of Khomeini who was gunned down Tuesday outside his office at Tehran Unversity's theological department. Opponents of the theocratic nature of the Iranian rule have been blamed but no one has been charged.

A crowd of mourners gathered in front of the U.S. Embassy here -- the first big demonstration there in three weeks -- while most of the procession marched to the burial site.

The dead man's son, Sadeq Mofatteh, 22, climed on a parapet next to the gates of the embassy to tell the crowd that he believed his father was killed by the CIA.

"The CIA killed everyone who was against the revolution. They killed my father because they wanted to change the course of the revolution," said the son.