Two months after the Iranian Experts' Assembly nominated 63-year-old Ayatollah Hussein Ali Montazeri as the eventual successor to the temporal and spiritual leader, Ayatollah Ruhollah Khomeini, the decision has not been ratified by Khomeini.

Iranian officials say more than two-thirds of those meeting as the Experts' Assembly -- a conservative panel of clergymen charged with nominating a supreme leader and the Leadership Council -- declared Montazeri "acceptable to an overwhelming majority of the people for future leadership."

But the number of experts present has not been disclosed and the way the decision was made public was odd, an apparently casual mention of it three days afterward by the Friday prayer leader in Qazvin, 100 miles west of Tehran.

It was then picked up by two of the four daily newspapers in Tehran, but the government-controlled radio and television ignored it.

Observers attributed this handling of the announcement to an unwillingness to highlight future leadership while Khomeini was actively discharging his duties.

But at the same time, official sources said, the assembly decided to act to prevent a leadership vacuum should something happen to the 83-year-old Khomeini.

Montazeri, who like Khomeini is called an ayatollah and has been a close friend of the supreme leader for four decades, had been widely considered the leading candidate to succeed him, ahead of other top figures such as President Ali Khamenei, Prime Minister Mir Hossein Mousavi and Consultative Assembly Speaker Ali Akbar Hashemi Rafsanjani.

Underneath his genial appearance, Montazeri is said to be a tough man.

A Moslem diplomat who deals with Montazeri said, "Every time I meet him I come away feeling more and more impressed with him. He is his own man, and has grown with the job."

Already Montazeri's powers are substantial. He has the right to appoint the members of the Supreme Judicial Council.

He is the "supreme guide" for the universities and theological colleges. He oversees the workings of the assembly committee on land distribution.

Press and radio regularly carry reports of his meetings with officials and delegations.

Ties between Montazeri and Khomeini go back more than 40 years, to when Montazeri was Khomeini's student in Qom. In 1963, when Khomeini first confronted the shah, Montazeri sided with his former teacher. Eight years later, Khomeini, then in exile in Iraq, appointed Montazeri as his personal representative to receive religious funds.

Another student of Khomeini who has risen high is Khamenei, 46, now in his second term as president. He is general secretary of the ruling Islamic Republic Party and, like Rafsanjani, is a hojatoleslam, one rank below ayatollah.

Khamenei received a setback last May when his sister, Badri, and her children left Tehran to join her husband, Ali Tehrani, in self-exile in Iraq, with which Iran has been at war since 1980.

But Khomeini, apparently wanting to maintain continuity of administration, backed Khamenei for reelection.

He won, but his vote dropped from 95 percent to 84 percent.

Khamenei had reluctantly named Mousavi, 43, as prime minister after his 1981 election.

He was widely known to be unhappy with Mousavi's performance and hoped to replace him last year, but Khomeini publicly intervened.

Calling Mousavi's administration "a successful one under extremely complicated conditions," Khomenei said: "I don't consider it advisable to replace the Mousavi government."

Mousavi, an important leader of the ruling party, is a radical who believes in land redistribution, greater government control of the economy, nationalization of foreign trade, and the fostering of cooperatives, particularly in distribution.

He is opposed by an alliance of conservative clerics and bazaar leaders, who view the growth of consumer cooperatives being set up at the government's behest in mosques and workplaces as a threat to their own existence. They have the ear of Khamenei and also the conservative Guardians' Council.

Among Khomeini's radical lieutenants, Rafsanjani is the most prominent, and under his leadership the assembly has become an active and important institution.

Diplomatic observers here say that they regard it a deliberate policy of Khomeini to balance the conservative and radical forces within his regime, and not to let one prevail over the other -- at least during his lifetime.