Sheik Ibrahim Amin, the chief spokesman and most visible figure in the Iranian-backed Hezbollah, or "Party of God," welcomed a Syrian role in ending the American hostage crisis today but described the hijackers of the TWA airliner as the only real "power centers" to be reckoned with.

The hijackers have "given opportunities to everybody to contribute toward an arrangement for the release of the prisoners in Atlit," Amin said in an interview, referring to the hijackers' principal demand, for the release of 735 Lebanese prisoners, mostly Shiite Moslems, held in northern Israel. "And they, on their part, are ready to free the American hostages."

"We welcome Syria as a party to end this matter, provided it accommodates the demands of the hijackers," Amin said amid reports that the 39 American hostages in Beirut may be moved to the Syrian capital.

Asked whether Hezbollah, whose members are believed to have commandeered TWA Flight 847 on June 14, would prefer Syria to take charge of the crisis instead of Nabih Berri, leader of the mainstream Shiite Amal movement and Lebanon's justice minister, Amin replied:

"This is a very sensitive issue, and the real power centers in it are the hijackers. Any party entering as mediator or nonmediator will fail if not provided with the opportunity to succeed."

Amin said he would not deny or confirm that the original hijackers of the plane were from Hezbollah, declaring that the most important thing in the affair was that "they were able through this event to air a just cause, and one that should be endorsed."

"But until now America has not dealt with the opportunities given to it in a responsible manner," he continued, urging the American people to link the hostage crisis with release of the Atlit prisoners despite what he called the refusal of the U.S. government to do so.

Amin expressed fears of American reprisals against his group after the hostage crisis was over.

He confirmed that his group receives financial assistance from Iran, saying, "Iran supports us as well as all the downtrodden people in the world and forces fighting for freedom. This is something that is evident and not a secret."

Although he declined to estimate the number of Iranian Revolutionary Guards based in the Bekaa Valley town of Baalbek, where he lives, Amin said they were "helping to carry the Iranian experiment to Lebanon." Pressed on whether the Iranians were training Lebanese Shiite guerrillas, Amin replied, "Revolution is not only training, it is thought, spirit and will. It is the formation of a personality that has faith in God and, of course, in arms."

Amin said the Iranian Revolutionary Guards should be credited for "building this personality of revolutionary Moslems and of resistance fighters to confront the enemy, which is a requirement of the Koran."

The Shiite cleric said that he visited Damascus last week to meet with the speaker of the Iranian legislature, Hojatoleslam Ali Akbar Hashemi Rafsanjani, and added that he has met many times with the Iranian leader, Ayatollah Ruhollah Khomeini.

By far the most radical of Lebanon's Shiite fundamentalist groups, though not the largest, Hezbollah is based in the Bekaa Valley but is also active in Beirut and in the Nabatiyah and Jibsheet regions of southern Lebanon. The majority of the 735 Atlit prisoners are thought to be followers of Hezbollah.

Informed sources have said that eight of the 13 hijackers usually guarding the TWA plane at Beirut International Airport are Hezbollah members and five are from Amal.

Another extremist Shiite group identifying strongly with Iran and with Hezbollah is Islamic Amal, led by Hussein Musawi, who split with Berri in 1982 when Berri defied Iran and joined a crisis committee of Moslem and Christian leaders.

Islamic Amal and Hezbollah leaders often hold joint meetings and espouse the same views. Amin said Hezbollah and Islamic Amal "were an indivisible part of one another. We are one and the same thing." Both operate out of Baalbek, which is under the control of Syrian troops.

Amin said his group's ties with Syria "were good and without problems," adding, "We aspire to have strong and effective ties with Syria so we can stand up to the Zionist enemy."

Amin was reluctant to comment on Berri's management of the hostage crisis. Hezbollah and Amal compete for influence and recruits within the lower ranks of the Shiite community. The young men guarding Amin's Beirut headquarters said they were paid roughly $100 a month, twice what Amal offers.

Amin insisted that there have been "no special or specific ties with Amal, no consultations," during the hostage affair. He dismissed Berri's role as the negotiator for the Atlit prisoners' release, saying, "What is important is that the demands are met, regardless of who happens to be negotiating."

Amin said he doubted that the hijackers had approved Berri's offer to move the hostages to a western embassy in Beirut. "If the hijackers really agreed to his proposal, they should have made a statement to that effect," Amin said.

Amin refused to condemn the hijacking, saying he would only do so if those criticizing the act joined him in condemning all the injustices of the world, specifically those committed by Israel against the Lebanese people. He said Hezbollah would use its influence with the hijackers only in urging them to hold to their demands.

The Hezbollah spokesman refused to go into details of the identity of the hijackers. "The hijacking is an event," he said. "Who is behind it, who carried it out, is beyond discussion." Is there a region, a power behind them? "I don't know," he replied. "This issue is closed."