Iranian President Abol Hassan Bani-Sadr, ending a long period of political silence, accused his enemies in the conservative Islamic clergy yesterday of committing abuses reminiscent of the late shah and suggested that the mullahs are continuing torture of political prisoners.

Bani-Sadr's strong attack on the fundamentalists, in a speech on the Moslem holiday of ashura, represented his sharpest public salvo in a dispute piting him and his moderate associates against the clerical hard-liners of the Islamic Republican Party who wield decisive influence in parliament and in the government of Prime Minister Mohammed Ali Rajai.

Their differences, which were muted in national solidarity at the outbreak of the war with Iraq, have surfaced with renewed intensity in recent weeks in behind-the-scenes discussions about Iran's conditions for release of the American hostages and U.S. responses now under study in Rajai's government.

Bani-Sadr's remarks, to a throng of his supporters in Tehran, brought the struggle starkly into the open dispite a unity plea earlier this week from Ayatollah Ruholllah Khomeini, patriarch of the Iranian revolution. They appeared to signal the end of Bani-Sadr's exclusive concentration on the war with Iraq -- he has spent most of the last month in embattled Khuzestan Province -- and his relative aloofness from the political infighting of Tehran.

"We had our revolution to overthrow the treacherous Pahlavi regime and prevent it from returning," Bani-Sadr said, referring to the late shah Mohammad Reza Pahlavi, Agence France-Presse reported. " Under that regime, the law was a pretext to be used against opponents and the people. Are we going to repeat that practice under this government?"

In an oblique accusation likely to touch tender nerves in Iran, Bani-Sadr went on to suggest formation of a special commission to study the country's prisons and "investigate whether there is torture or not," according to Reuter news agency.

He accused the mullahs, or clergymen of trying to clothe their "monopolistic domination" of the country in legal authority and urged that the judicial system be kept independent of political power to avoid repetition of the abuses committed by SAVAK, the late shah's secret police, AFP said.

Bani-Sadr's call for an investigation into prisons was believed to be the first time a prominent revolutionary figure has raised the possibility that torture is continuing in Iranian prisons under the Islamic government headed by Rajai with the overall moral and political authority of Khomeini.

Opposition to torture of political dissidents under the shah, including Rajai himself, has been a major theme of Khomeini's revolution. Any suggestion that is continiuing -- particularly a public one such as Bani-Sadr's yesterday -- is an explosive charge and a measure of the struggle under way between the president and his political foes amnong the mullahs.

Correspondents in Tehran noted that Bani-Sadr avoided specific mention of the Islamic Republican Party, making his charges instead by allusion. but, they reported, the meaning was clear to the thousands listening to his speech in the context of last week's imprisonment of former foreign minister Sadegh Ghotbzadeh and anticlerical protests demanding his release.

Mindful of Khomeini's moral sway in the dispute, Bani-Sadr attempted to portry his foes as rebels against Khomeini's orders for revolutionary unity. Those who disregard Khomeini's efforts to join the clergy and the intellectuals, he said, are not true Moslems.

" True Moslems are those who do not surrender to advocates of force and do not impose force when they are in power," he added, according to AFP. a

A backdrop to his complaints was an attack Tuesday by masked men swinging big sticks who ransacked the Tehran offices of the newspaper Mizan, a relatively moderate organ begun 10 weeks ago by the brother of former prime minister Mehdi Bazargan. Although the attackers did not reveal their identity, they were believed to be fundamentalist youths acting on an exhortation from Khomeini Sunday to "resist" newspapers with articles reflecting views of "those who want to remove the clergy from the political scene."

Bani-Sadr also suggested that the power struggle distracting Tehran is harmful to the war effort against Iraq. This is particularly true, he added, among professional Army officers whose authority reportedly has been questioned by clerical leaders.

"They must be sure that behind them a psychological war is not developing, and I have been obliged to tell our armed forces commanders several times that this has stopped happening," Bani-Sadr said.

Official Iranian reports yesterday said Iranian forces were resisiting Iraqi troops still pressing on the town of Susangerd in Khuzestan. Iran claimed Monday to have pushed the Iraqis out of Susangerd in what was described as the largest battle of the Persian Gulf war. Yesterday's reports called the fighting "mopping-up" operations, Reuter said.

In Tehran, Rajai put off for a day a meeting scheduled with former Swedish prime minister Olof Palme, dispatched to Iran as a special peace-making envoy by the United Nations. Iranian officials explained to correspondents that Rajai returned late from a trip to the war front.