Iran's parliament today postponed debate on the U.S. hostages for the third time in a week and instead went into closed session to discuss the war with Iraq.

The hostage issue was on the agenda, but after a brief open session at which there was no reference to the captives, 15 legislators asked the assembly to talk about the continuing fighting between Iranian and Iraqi forces. The Majlis, or parliament, had been due to set up a special commission to consider the hostage issue and recommend terms for the release of the 52 Americans who were seized by militant students on Nov. 4.

President Abol, Hassan Bani-Sadr, meanwhile, said that the hostages' situation could worsen because of the war with Iraq. In a telephone interview with Newsweek, he also insisted that Iran still requires a U.S. apology as a condition for the captives' release, and he warned that Iran might try to close the Strait of Hormuz if its military situation deteriorated.

Bani-sadr accused the United States of helping Iraq to plan the war with Iran. "From the very beginnning, they were neutral," he said. "They were involved in the planning of the war."

Asked if the war would change the sitution of the U.S. hostages, Bani-Sadr said: "For the moment no. But if the international situation gets worse, it could get worse for the Americans sending military aid to the Iraqis. If no, the hostage situation will certainly worsen."

The Iranian president listed two conditions for cease-fire: "that the Iraqis withdraw their troops from the border and stop interfering in Kurdistan and Khuzestan," two Iranian provinces bordering Iraq that have been troubled by autonomy-seeking regional minorities.

Asked by Newsweek's Elaine Sciolino whether Iranians might try to blockade the Strait of Hormaz if they became isolated in the Persian Gulf, Bani-Sadr replied: "Yes, it's a possibility. If we're attacked on all sides we're certainly not going to sit with twiddling thumbs. We'll use everything we have in our power."

Insisting that Washington must still apologize for its past support of the late shah as a condition for the hostages' release, Bani-Sadr said Ayatollah Ruhollah Khomeini "simply forgot" to include this demand in his recent statement listing four conditions for freeing the Americans.

Bandi-Sadr's warning that the war with Iraq could have a negative effect on the hostages followed a similar statement two days ago by Ayatollah Hossein Ali Montazeri, who is being groomed to succeed Khomeini as Iran's Shiite moslem spiritual leader. Montazeri said the conflict would delay a settlement of the hostage issue.

Today, parliament Speaker Ali Akbar Hashemi Rafsanjani told the assembly that since Iraq started the war, it must take the first steps to end it.

Commenting on the possibility of outside mediation to end the fighting, Rafsanjani aid the parliament would make the ultimate decision on whether to continue the war, according to Tehran radio.

"Our general policy so far has been that we have not wanted this war," he told parliament.

"[Iraqi President] Saddam Hussein gave the orders to attack our military bases and the Iranian response was to attack theirs.

"They also attacked our economic and cultural centers, leaving the Iranian Army unable to take revenge because the innocent Moslems of Iraq are our brothers," the speaker said.

"Our last words to those who are coming to mediate is that we have not started the war, so we should not take the initiative for a cease-fire.

"As long as the Iraqis are in a state of war and have not stopped their violations, generally we have nothing to say," Rafsanjani added. CAPTION:

Picture, ALI AKBAR HASHEMI RAFSANJANI . . . "we have not started the war"