The acting speaker of Iran's new parliament said today that a decision to release the 53 American hostages or try them as spies probably will be taken in late July, a month later than previously estimated. He ruled out any action on the hostage crisis before then.

Yadollah Sahabi, interviewed by the state radio, said consideration of the hostage crisis will have to await the formation of a new government, expected to be inducted into office sometime between late June and early July, and then a debate of the new programs that the government will introduce.

"I think one must certainly wait till the third week of July for the debate on the hostages," Sahabi said.

Sahabi said parliament, empowered by Ayatollah Ruhollah Khomeini to decide the hostages' fate, will not even begin its official business until it elects a permanent speaker during the next three weeks.

"After the parliament becomes official, it will take some time for the new government to be introduced," he said. "Then, the members of the government will take time to introduce their program."

Following that, the deputies will debate the government program and finally vote the new government into office. Only after all of those formalities are finished will the fate of the hostages, now held for 208 days, come up for debate, Sahabi said. Previously, Iranian leaders had said the issue could be debated in late June.

Moslem militants holding the hostages said yesterday, as the parliament was formally inaugurated, that it would have to furnish "an acceptable reason for the people of Iran" if it decided to free the hostages.

The challenge was the latest in a series directed at the parliament, whose dominant fundamentalist members have already indicated they will vote for spy trials.

Today the parliament adjourned its public sessions for a week to allow parliamentary committees to review members' credentials. The Interior Ministry has already disqualified 21 of 242 members chosen in recent elections. The body is to have 270 members eventually. Sahabi was elected yesterday as temporary chairman.

[State Department spokesman Thomas Reston said at least five hostages recently have sent letters to their families in the United States, the first such communications since the failure of the U.S. hostage rescue attempt April 25. Reston said he did not know from what locations the letters were sent.]

In the aftermath of the rescue bid, the militants said they dispersed the hostages among 17 Iranian cities including Tehran.

One of the new hostage locations is said to be a residence in the northeastern Iranian city of Mashad. Militants there said today that unidentified gunmen fired on the house and then fled, the official Iranian news agency reported.

Militants at the occupied U.S. Embassy in Tehran reported another incident, saying Revolutionary Guard outside the mission fired into the air last night when they spotted a suspicious-looking automobile nearby. The car quickly left, they said.

No injuries were reported in either incident.

Several such unexplained shooting episodes have been reported in recent weeks around the Tehran embassy, and the militants have repeatedly blamed "U.S. agents" for them.