The U.S. military's recent rescue from Somalia of 260 people, including the U.S. and Soviet ambassadors, was a daring operation involving waves of Marine helicopters flying from two Navy ships into the heart of the war-torn capital after being unexpectedly diverted from Operation Desert Shield, according to U.S. officials.

The evacuation, accelerated suddenly last Thursday after an urgent plea for help from the U.S. Embassy in Mogadishu, required two Marine helicopters to conduct rare, nighttime refuelings in midair while traveling at more than 125 mph, the officials said.

After touching down on the embassy's lawn, the massive CH-46 Sea Knight and CH-53E Super Stallion helicopters then had to dodge pitched battles in the capital as they ferried out those holed up inside the embassy compound -- including a baby daughter of the Sudanese ambassador born there while awaiting rescue, the officials said.

Additional helicopter flights were conducted over the next 48 hours to empty the compound of all personnel following the hurried destruction of all cryptographic and communications equipment and sensitive documents. Throughout the operation, battles raged in the street outside the compound, but none of the helicopters was shot at or had to do any shooting.

Shortly after the evacuation, looters used rocket-propelled grenades to blast open the embassy's doors and strip it of anything that "wasn't nailed down," a State Department official said, based on reports from foreigners who left later. Fighting continued throughout Mogadishu yesterday, and hundreds of corpses piled up in downtown streets, as the nation's president, Mohamed Siad Barre, and his supporters fended off military assaults by rival tribes, the official said.

Senior diplomats from more than 10 nations were rescued in the U.S. operation, later judged "flawless" by Gen. Alfred M. Gray, the Marine commandant. He said in an interview that the helicopter refueling operation was evidently the first of its kind performed during such a lengthy flight ashore from ships.

Other officials said the Marine Corps' rescue of the Soviet ambassador and 35 of his staff, who had been ferried to the U.S. Embassy after elaborate consultations in Washington and Moscow, added another exceptional dimension to the operation following three decades of bitter superpower competition in the poverty-stricken nation.

The current battle between rival clans for control of Somalia evidently originated in the slayings of more than 20 people by government soldiers in retaliation for the looting of a government warehouse by suspected rebels late in December. The shootings had caused the U.S. Embassy to order the departure of all but 40 government personnel from the 80-acre compound in Mogadishu.

More than 200 foreigners and 26 U.S. citizens subsequently sought refuge inside the compound's 10-foot-high walls from widespread looting and anarchic conditions.

A senior State Department official, who spoke on condition that he not be identified, said the U.S. military rescue was accelerated Thursday morning when U.S. Ambassador James K. Bishop urgently cabled Washington that armed looters had entered the embassy compound and threatened the lives of the people there. Bishop warned that the staff might not survive until a planned evacuation on Saturday.

The USS Trenton, which was stationed in the Indian Ocean for Operation Desert Shield, immediately launched two helicopters packed with 70 Marines trained for special operations on a harrowing nighttime flight into the middle of the Somalian civil war.

During the 460-mile flight ashore, each helicopter was refueled twice by fixed-wing, KC-130 tankers that took off from Bahrain in the precisely timed operation. "Just finding one another {in the middle of the night} is enough of a challenge," said Marine spokesman Fred Peck.

Fearing that the helicopters would be fired on if regarded as a military reinforcement for one of the rival Somali groups, U.S. diplomats tried unsuccessfully to provide advance notice of the arrival. "We couldn't reach the Somali government, and hadn't been able to for days, because there doesn't seem to be a government," one official in Washington said.

By the time the helicopters arrived on Friday morning, touching down just inside the gate from a street littered with corpses, the looters had been repulsed with small-arms fire by hired security guards, but an embassy building had sustained a direct hit from a rocket-propelled grenade, according to State Department officials.

After a special plea for help from officials at the Soviet Embassy in Washington and Foreign Ministry in Moscow, U.S. officials in Mogadishu had arranged for all Soviet Embassy personnel to be escorted more than a mile through the capital's tense streets by forces loyal to Siad Barre and brought into the U.S. compound.

The convoy of armed vehicles was arranged after Soviet officials here disclosed the special radio frequencies used for Soviet diplomatic communications in the Somali capital, allowing direct communication between the U.S. and Soviet staffs after normal telephone and telex service had ceased. Soviet Foreign Minister Eduard Shevardnadze spoke twice with Secretary of State James A. Baker III by telephone about the evacuation on Saturday, U.S. officials said.

Peck said that shortly after arriving, the Marines on the first two helicopters deployed around the embassy's perimeter. "There were ladders seen up around the embassy walls prior to their arrival, so they felt they were in some danger," he said.

Some of the Marines were immediately dispatched to the U.S. Office of Military Cooperation two blocks away, where several U.S. officials and the Kenyan ambassador had been trapped by local gunfire.

The first two helicopters lifted off from the embassy compound on Friday with 62 people. The remainder were flown out Saturday by five helicopters launched from the USS Guam, an amphibious assault ship. The Guam and the Trenton, an amphibious transport dock, are homeported at Norfolk.

In all, 260 citizens from 30 nations were ushered to safety aboard the two ships by late Saturday and are expected to be unloaded later this week at Muscat, Oman.

The Associated Press reported yesterday from Mombasa, Kenya:

Heavy fighting between Somali rebel forces and troops loyal to Siad Barre raged in the streets of Mogadishu, preventing the continued airborne evacuation of foreign nationals and Somalis hoping to escape the bloodshed.

Most Westerners evacuated from Mogadishu and most still in the city are Italians, and officials heading an Italian-led evacuation effort from Nairobi said that flights to the Somalian capital were considered too risky. "We will try again tomorrow," the official said.

An Italian frigate, which had been in the Persian Gulf helping maintain the international economic embargo against Iraq, also was due off Mogadishu for possible use in new evacuations, according to Foreign Ministry officials in Italy, a former colonial power in Somalia.

The French Embassy in Nairobi said helicopters from a French frigate off the Somalian coast picked up 47 people -- including 27 Italians -- from Merca, 40 miles south of Mogadishu and ferried them to safety.

Rebel radio broadcasts claimed that the insurgents -- loosely allied factions of clan-based guerrillas -- had gained control of almost all of Mogadishu.