Iranian security forces used tear gas to disperse demonstrators in the northwestern city of Tabriz today as supporters of Shah Mohammad Reza Pahlavi continued to cast around for a civilian government capable of appeasing the country's religious and political opposition.

Conflicting accounts of army insubordination yesterday in Tabriz and in the Shiite Moslem shrine city of Qom accelerated what one diplomat called the "rumor mill warfare" sweeping the country. Versions of army behaviour in Tabriz ranged from fraternization with protestors against the shah to wholesale desertion.

Perhaps more important than what actually happened, military analysts say, is the fact that many Iranians, including soldiers, believe the rumors rebounding across the country in the absence of newspapers and uncensored Iranian radio reports.

Stories of desertion and various antigovernment incidents within the armed forces are spreading like wild-fire in army barracks and serving to further erode military morale, the sources said.

Opposition National Front sources said the Tabriz events were hastening efforts to form a civilian government to replace the military-led regime installed last month to quell disorders. The sources said attempts were under way to form a Cabinet under former National Front member Gholam Hussein Sadighi, 73.

Sadighi refused to comment, but his daughter said by telephone that the shah had offered him the job during a meeting Sunday.

"He has not given his answer yet," she said. "The matter is still under consideration."

In the oil sector, production rose to 3.3 million barrels as more field and refinery workers returned to their jobs because of tough military action against strikers. The crude output was up by some 700,000 barrels a day and could be expected to reach full production of about 6.5 million barrels a day in another week, if the trend continues, industry sources said.

According to the official Iranian radio, no one was injured when security forces dispersed today's demonstration in Tabriz, the second in as many days. Officials said the march included several hundred doctors and nurses protesting attacks on hospitals in the northeastern city of Mashad last week in which two persons were reported killed.

A National Front spokesman said today's Tabriz demonstration was handled by several hundred Iranian Special Force commandos flown into the East Azarbaijan provincial capital last night after army discipline cracked.

The spokesman claimed "hundreds of soldiers" participated in the demonstration yesterday after a religious leaders's speech won their sympathy, and that 45 of them deserted their units and slipped away into the crowd. He said the rest eventually returned to barracks without incident.

The National Front spokesman also said "several soldiers" in Qom went to the house of the country's leading resident Shiite figure, Ayatollah Seyed Khem Shariatmadari, and turned in their automatic weapons. He said the house was then cordoned off by troops.

Even more serious than these incidents in the long run may be the attitude of the officer corps, long considered unflinchingly loyal to the shah and presently seen as his main source of support.

"Increasing numbers of officers are questioning whether the shah has become a liability," a Western diplomat said. "A few months ago they were questioning the speed of his liberalization programs but now they have doubts about whether he's of any use at all."

a spokesman for National Front leader Karim Sanjabi said some members of the front had been contacted about participationg in a civilian government under the shah as a figure-head monarch, but that they refused. He said Sanjabi himself had not been approached since his earlier refusals of the shah's request to form a government.

Despite rumors that such a move is imminent, senior National Front figures doubted the government under Sadighi would be formed because of his age and reputed ill-health. One source described the condition of Sadighi, who withdrew from the National Front 15 years ago, as "extremely nervous and debilitated."

Washington has been promoting the efforts to form a civilian government, although U.S. officials deny they are "interfering in internal politics." But other observers were taking a more critical view of such efforts.

A European diplomat said the main aim of Iranian politicians negotiating on a civilian Cabinet "seems to be to keep the military government from working." A17