Prime Minister Mohammed Ali Rajai of Iran said today that the United States could encourage Iran to release the American hostages by withdrawing its AWACS reconnaissance planes from the Persian Gulf and preventing Jordan from helping Iraq in its war against Iran.

Rajai's statement at an extraordinary news conference here during which he bared his foot and put it on a table to display what he said were traces of torture, marked Iran's first public attempt to use the 52 American hostages as a lever to influence Carter administration policy on the Persian Gulf war.

It underscored an impression conveyed by Rajai today and last night in an address to the Security Council that Iran believes the United States is among a group of nations backing Iraq in the war as part of an international conspiracy against the revolutionary Islamic government of Ayatollah Ruhoillah Khomeini.

This attitude contrasted sharply with the speculation earlier this week that Rajai's two-day visit here could lead to negotiations between him and U.S. officials on the possibility of a U.S.-Iranian tradeoff -- release of the hostages in exchange for U.S. military equipment and spare parts for the hard-pressed Iranian Army and Air Force.

U.S. diplomats here said that the possibility of such talks was never very bright and that it now seemed dimmer than ever. Rajai reiterated his refusal to meet with any Americans on the hostage issue and said instead that the Iranian parliament will soon lay down its final conditions for their release, the only ones Iran will consider.

"I could tell you with assurance that the moment the parliament, or Majlis, makes its decision, which I think . . . is not far away, for my government the question will be final and solved," he said.

In the meantime, he suggested, the United States should pull back the four AWACS (airborne warning and control system) flying radar planes dispatched to Saudi Arabia for what the United States called the Saudis' "legitimate defense needs" soon after the Iranian-Iraqi war broke out Sept. 22.

Rajai charged last night that these planes are supplying intelligence to Iraq, and he said U.S. and Saudi fears of a possible attack on gulf Arab nations friendly to Iraq are only pretext.

Similarly, Rajai urged the United States to stop King Hussein of Jordan from allowing supplies to move to Iraq through the Jordanian port of Aqaba, implying that Jordan is cooperating as part of the U.S.-led plan aimed at Iran.

"When our people look at this, it would be very hard for them to become convinced to get rid of this [hostage] problem," he said. "There is an assortment of such actions [the Americans] could undertake that would be removing the acts that are considered in Iran as actions against the Iranian people. That in itself would be a great step toward freeing the hostages."

Although eclipsed by Rajai's statements on the hostages, consultations continued with little hope of success on U.N. efforts to bring about a cease-fire in the war. Rajai and Iraqi Foreign Minister Saadoun Hammadi said afterward, "I don't think there is anything concrete developing."

Rajai left New York tonight aboard the special Iran Air flight that brought him here. He was bound for Algiers, according to officials.

At the news conference, Rajai said, surprisingly, that Iran's demand for an official apology from the U.S. government for American intereference in Iranian affairs during the rule of the late shah would be easy to resolve in any deal for release of the hostages. This is so, he said, because the Carter administration already has made the apology, if only informally.

"The passage and time and what we have heard from responsible people in the [U.S.] government and other officials close to the government, for us it seems that this condition in practice already has been answered," he said. "All it needs is probably to put something on paper."

Rajai did not say what form the apology he was talking about had taken, or who relayed it. President Carter has said the United States will not make such an apology and neither the State Department nor the White House had any comment on Rajai's remarks.

Rajai's statements seemed to be an effort to remove this question as a sticking point in whatever set of conditions the Iranian parliament lays down for the hostages' release.

Rajai, speaking in Persian, relayed in English by an Iranian translator, also went out of his way to affirm that his government has the authority to release the hostages if the United States meets the parliamentary conditions. r

This came in response to questions arising from earlier U.S. efforts to work through President Abol Hassan Bani-Sadr, who proved unable to deliver on promises made to Waldheim and others who tried to negotiate a hostage release.

"I would give you a 100 percent assurance that the decision of the Majlis, which has been given in advance of the support of our leader, the Imam Khomeini, will be fully carried out," Rajai pledged.

Rajai charged that President Carter and his aides are demonstrating concern for the hostages as an electoral tactic, and that in reality they are not interested in getting them freed. This was proved by the April 25 attempt to liberate the hostages in a commando raid, he added, because had the U.S. mission gone any further the hostages would all have been killed in the fighting.

"For the people of Iran, the issue is not the American election," he said. "For us the issue is the hostages and solving the question, not electing the president of the United States."

Rajai, a 46-year-old former school teacher with little government experience, appeared at the news conference unshaven and tieless. He was flanked on the right by Ali Shams Ardakani, the Iranian delegate here who interpreted, and on the left by a bearded Iranian wearing corduroy trousers and a khaki fatigue jacked who offered advice at several points.

After reviewing alleged U.S. wrongs that he said led to the hostages' capture, Rajai expressed sympathy for their families and understanding for relatives' concern.

"I know how they feel," he said. "I know how they suffer, because I myself have been a prisoner, but not a simple prisoner. And several of my colleagues in the government have been prisoners and have been tortured."

Rajai said his family never knew where he was when he was in prison and that he was tortured daily. His nails were pulled out and the soles of his feet were beaten, he said.

At that point Rajai pulled the shoe and sock off his right foot and exhibited the bare foot to reporters to show what he said were marks left by the beating.