Leftist students defied government orders to turn over their campus sanctuaries to President Abol Hassan Bani-Sadr's forces today and touched off running battles with Moslem fundamentalists seeking to break leftist influence at Tehran University.

The clashes, the most serious in an increasingly tense conflict in the capital between left-and right-wing groups, coincided with fighting on at least two other college campuses in the southern city of Shiraz and a fourth day of fighting in Kurdistan between government forces and rebellious Kurdish guerrillas.

Rifle and automatic weapons fire resounded well past midnight at the Tehran University campus as leftists apparently held onto positions in defiance of an order from Bani held onto positions in defiance of an order from Bani-Sadr to withdraw by midnight or face expulsion by the Iranian "masses."

[Bani-Sadr said in a radio broadcast Tuesday morning that the last of the student political groups left the university by 2 a.m.]

There were conflicting casualty figures from the clashes, and the results of the nighttime shooting could not immediatley be determined. One spokesman at nearby Khomeini Hospital said more than 100 persons had been injured all but three of them slightly, and that two young men had been brought in dead. A short while later, however, another official at the hospital said eight Iranian had been killed and as many as 500 injured.

In the Kurdish region, Iranian Army units reportedly shelled the town of Saqqez, killing 15 persons, according to a spokesman for the Kurdistan Democratic Party.

An Army communique said that 20 soldiers were killed and 36 wounded when Kurdish rebels attacked an Army column near the provincial capital of Sanandaj.

Kurdish sources said that 320 guerrillas had been killed in the recent fighting, which has coincided with skirmishing between Iranian forces and Iraqis across the countries' common border.

The Tehran University clashes began with rock throwing and fist fights this morning as Revolutionary Guards fired their rifles into the air to disperse a crowd estimated at 20,000.

Most political groups removed their offices from the campus in compliance with Friday's government order but the Marxist Fedayan guerrilla group spearheaded an attempt by some leftists to remain on the campus. By nightfall, the Fedayan appeared to control a street running alongside the campus and were resisting attempts by Moslem fundamentalists to take over their strongholds in university buildings under covering fire from Revolutionary Guards.

In Shiraz, 400 persons, including two senior police officers, were reported injured in fighting between rival groups after security forces failed to disperse them with tear gas.

The leftists' defiance of the government's order to withdraw from campuses was met tonight by an ominous warning from Ayatollah Ruhollah Khomeini, who commands the absolute loyalty of millions of devout Iranian Moslems.

"If some groups continue their resistance, I will pronounce my last words to the nation," Khomeini said in what was taken as a threat to call out his followers en masse to crush the leftists.

Khomeini said he wants "all connections with the West and the East" to be abolished in the university system.

In a series of broadcast appeals for political groups to heed the government's orders, Bani-Sadr said that he would lead a Revoluntionary Council delegation to Tehran University Tuesday to demand the evacuation of the campus, but he called on the people to be disciplined and not undertake any action on their own to evict the remaining groups.

The government began its campaign to purge Iranian colleges after a Moslem fundamentalist group allied with the militants holding the U.S. Embassy in Tehran took over several campuses around the country. The group, called the Students Following the Line of the Imam, demanded a purge of leftist students and teachers as part of an Islamic "cultural revolution."

Diplomatic sources said Bani-Sadr's government apparently launched its own campaign for an Islamic university system to avoid being outflanked by the Moslem students as it has been repeatedly during the embassy crisis.