Iran's ruling Revolutionary Council is seriously considering urging the militants at the U.S. Embassy to release American hostages not suspected of espionage, according to several council members.

Despite the growing evidence of high-level support for such a partial release, however, neither Ayatollah Ruhollah Khomeini nor the hostages' student captors have given any hint that such a move may be imminent.

The students still publicly insist that only the return of the deposed shah will bring about the hostages' release. A spokesman at Khomeini's headquarters in the holy city of Qom today professed to know nothing about immediate plans to free any hostages.

But Ayatollah Hossein Ali Montazeri, chief mullah of Tehran and a Revolutionary Council member, said tonight that the council had accepted such a proposal, although it had not received final approval from Khomeini, Iran's spiritual and temporal leader.

Because of the hydra-headed nature of central authority in Iran, it was difficult to assess the likelihood of a partial release of the hostages.

But observers noted that not even the students at the embassy had issued a flat denial of the Revolutionary Council's proposal, even though they insisted that only they had the power to decide when or whether the hostages should be freed.

Besides Montazeri, both Foreign Minister Sadegh Ghotbzadeh and Finance Minister Abol Hassan Bani-Sadr were quoted by Tehran newspapers today as predicting, a swift release for some hostages not suspected of spying.

According to the "evidence" cited publicly by the students, fewer than half a dozen of the 50 hostages have been openly accused of being officers of the Central Intelligence Agency.

To outward appearances, this would seem to leave the majority of the hostages eligible for the partial release, with the remaining hostages presumably retained for some sort of political show trial.

It was unclear, however, whether only suspected CIA employes would be ineligible for the proposed early release of whether the definition would be interpreted more broadly to include routine reporting by such embassy officials as political officers and commercial attaches.

Past experience has shown that a final decision probably lies with Khomeini, the only authority figure who appears to command the respect and obedience of the students.

The upbeat statements from Ghotbzadeh and Bani-Sadr seem calculated to create momentum in favor of their own moderate position in the debate within the Revolutionary Council. Council members said they have been discussing a release at recent meetings. But nothing decisive can be accomplished until Khomeini hands down his opinion, they added.

The maneuvering illustrated the three-way diffusion of power that has complicated efforts to arrange for the release of hostages -- or even decide whom to deal with.

The Revolutionary Council, in principle, manages the country's afairs. The Islamic militants who occupy the embassy, clearly refuse to recognize its authority. Only by appealing to Khomeini's direct intervention with the students can the Council have its wishes carried out.

It is this diffusion of power that has contributed to delays and disorder in setting up the international "grand jury" advocated by Iranian officials for hearing the alleged crimes of the United States and the deposed shah against the Iranian people. There also had been suggestions, endorsed by Khomeini, for a separate international tribunal to try the hostages against whom espionage charges are brought. Sean MacBride, former head of Amnesty International, left Tehran yesterday after two days of discussions with Revolutionary Council members on some kind of international jurists' panel. On departure, he expressed qualified optimism that progress had been made, at least at the level of his contacts.

Ghotbzadeh told the Tehran newspaper Ettelaat that the grand jury will begin hearings during the first week of January. He said nothing about any hostage trial, however, and student spokesmen in the embassy insisted that no tribunal has been organized for hearing charges against the hostages.