The U.S. Embassy, warning that it can no longer protect American lives, set an emergency evacuation plan into motion today as bloody clashes were reported in Tabriz and other provincial cities between the new revolutionary government and rival insurgent groups.

The embassy, which was stormed by street fighters yesterday, said it "strongly recommends" that all Americans leave Iran. It announced an airlift scheduled to begin Saturday from Tehran's Mehrabad Airport, which has been closed for a week.

[Tehran radio announced that the revolutionary government executed four of Shah Mohammad Reza Pahlavi's generals before dawn Friday, according to news service reports. The generals, who died before a firing squad at the headquarters of Ayatollah Ruhollah Khomeini, included Nematollah Nassiri, the former chief of the shah's dreaded polic, SAVAK. Others were the commander of the paratroop corps, the martial law commander of Tehran and the governorgeneral of Isfahan.]

Estimates of the death toll in the Tabriz fighting ranged from 100 to several hundred. The city lies about 350 miles northwest of Tehran and reports were sketchy, but the fighting was said to pit forces loyal to the new Islamic government of Prime Minister Mehdi Bazargan against opponents variously described as pro-shah agents of SAVAK, the secret police, and leftist guerrilla groups defying orders to turn in their weapons.

The Tabriz clashes, along with continuing gunfire and attacks in Tehran, reinforced growing fears that Khomeini's provisional government will be unable ao assert its authority quickly enough to prevent a violent power struggle.

An important test of Khomeini's control over the situation will come on Saturday, the day the Moslem leader has called on Iranians to end the general strike that has paralyzed the country and reopen all universities and schools.

The Tehran University campus, however, has been turned into a combination arsenal and combat training center by leftist guerrilla groups, including the People's Sacrifice Guerrillas and the Islamic Mujahadeen. Both groups have pledged to keep their guns and continue the revolution.

About 5,000 soldiers, airmen and police backed by leftist groups rallied today at Tehran's Technical University to protest Bazargan's top military appointments.

"We will not surrender our weapons," they chanted.

Clashes similar to those in Tabriz also were reported in Rezaiyeh, capital of West Azerbaijan Province, Sanandaj, capital of Kurdestan Province, and Kermanshah, near the Iraqi border.

Gunmen looted stores and shops in downtown Tehran last night, underlining the lawlessness in the capital since military weapons stores were raided last weekend in the final hours before the fall of Shahpour Bakhtiar's caretaker government.

About 50 pro-Khomeini guerrillas attacked the Moroccan Embassy today, briefly detaining Ambassador Ghali Benihama during a search for arms. A Moslem mullah, or clergyman, later came to apologize for the incident.

The shah has been in Marrakesh, Morocco, as a guest of King Hassan II since soon after his departure for apparent exile Jan. 16. He and his family moved to Rabat, the Moroccan capital, today after Hassan left for a visit to Paris, news services reported.

[Meanwhile, the government radio announced that Bazargan's Cabinet issued a decree early Friday confiscating all properties in Iran belonging to the shah and the rest of the royal family, news services reported.]

Khomeini aides reacted coolly to requests from the U.S. Embassy for buses to move Americans to the airport for Saturday's evacuation. This was seen as a reflection of irritation at the evacuation preparations, which were interpreted as a lack of confidence in the new government's ability to restore order.

U.S. officials said a skeleton staff would remain at the embassy. An embassy source said Ambassador William Sullivan probably will be part of it.

Many of the approximately 2,000 Americans left in Isfahan, mostly defense contract employes, began moving into Tehran in preparation for the airlift.

In Tabriz, about 50 Americans also were preparing to evacuate. In all, an estimated 7,000 Americans remain in Iran. But the embassy said it did not know how many will leave in the airlift.

The British also began preparations to evacuate their 1,500 citizens here, establishing an evacuation staging area in north Tehran and scheduling flights for Friday.

A British Embassy official said buses with evacuees would leave Tehran under an armed escort provided by the "Islamic police force" created by Khomeini.

There also were private efforts to evacuate American employes, including a charter flight by Pan American Airways Friday to airlift employes of Pan Am, the Intercontinental Hotel and some U.S. government employes.

The Americans have been told that they can take one suitcase with them, and that they should limit their movements in the city until they leave.

About 45,000 Americans were in Iran before the turmoil began. Most of the 7,000 remaining are private citizens and cannot be forced to leave. About 2,000 are married to Iranians and the States Department in Washington said many of these probably will stay.

Turkey, after initial reluctance, has agreed to allow the United States to send five HH53 "Jolly Green Giant" helicopters and six C130 transport planes to a NATO base at Incirlik, near the Iranian border, to stand by for emergency use to haul passengers or refuel other planes, he said.

The Turkish government, however, authorized use of the base only on condition that the aircraft be unarmed, that they carry only a normal crew, that they be used only to evacuate Americans and their families and that any flights into Iran be approved by the Iranian government, Carter added.