Hundreds of disparate Americans flocked yesterday to Lafayette Square where they barraged 300 Iranian supporters of Ayatollah Ruhollah Khomeini with torrents of verbal abuse, and a scattering of eggs, tomatoes and bottles.

But there was no repeat of the widespread violence that marked a similar Iranian demonstration here on July 27.

District of Columbia and U.s. pArk police stood shoulder to shoulder in a circle around the Iranians, holding back a surging crowd of American tourists, government employes, office workers and students, allowing the foreign students to chant anti-American slogans and renew their complaints of police brutality.

The Americans, angered by the continued holding of the 52 U.S. hostages in Iran, pleaded with the riot-helmeted police to break ranks just long enough to allow them to charge the Iranians, who alternately shouted slogans and knelt in prayer.

"Give me that baby. I'll rip your baby's arm off," screamed one young man as a Moslem woman paraded near him.

"Give us just one of them," begged two young men in business suits.

"You're mine, you're mine," screamed a blond man wearing a blue Hotchkiss T-shirt, making eye contact with an impassive Iranian who sneered at him from the center of the circle.

"If one officer would move aside," suggested Charlie Miller, 19, of Manassas, straining against a police scooter that held him in tow. "I'd stomp those good-for-nothing Iranians."

Across Pennsylvania Avenue from yesterday's demonstration, White House Chief of Staff Jack Watson was told by the Justice Department that the Immigration and Naturalization Service (INS) is satisfied that all but two of the 192 Iranians arrested here July 27 are in this country legally.

Watson had asked Justice to investigate complaints by INS agents, made through a union representative, that agency officials had failed to check to see if the names given by the Iranians, after a 10-day silence, were their real names.

Justice official John Russell said the names were checked against a master list compiled last November when President Carter invoked a new, get-tough policy against Iranian students here.

Despite those statements, 50 INS agents in New York called in sick yesterday in protest.

State Department official David Passage also denied yesterday that the department had suggested that INS go easy on the students so that no harm would accrue to the 52 Americans being held hostage in Tehran.

Passage said State merely asked INS to "get the job done as quickly as possible," and hoped it would be accomplished "without further encumbering a difficult situation" regarding the hostages.

In another development yesterday, former U.S. attorney general Ramsey Clark told a press conference that the arrests last month were "unwarranted in fact and illegal in law." Clark said the error of the arrests was compounded when the students were "not only detained, but . . . placed in leg irons and handcuffs and transported hundreds of miles."

The 192 arrested last month were moved to prisons in New York after they refused to identify themselves. They were released Tuesday after giving their names to INS agents.

But more than 70 of those released from jail were held hostage inside a mosque in the Queens borough of New York City Wednesday night by an angry, flag-waving, beer-drinking crowd of neighborhood residents.

Those Iranians left the mosque in New York about 5:30 a.m. yesterday, under police escort, in cars and vans, and arrived here in time to participate in the demonstration.

The marchers also were joined in the park by about 40 Iranians who ended a hunger strike they had conducted for 11 days on the sidewalk in front of the White House.

While some of the police officers exchanged good-natured banter with the Americans in Lafayette Square, even laughing at some of the more outrageous threats, they stood firm against occasional sorties by the counterprotesters, and arrested three Americans for lobbing missiles over lines of police and media representatives into the circle of Iranians. All three Americans were released on bond a short time later.

D.C. Assistant Police Chief Maurice Turner said officers were told at roll calls before the rally to avoid taking 'any individual police action" that might stir up either the Iranians or the Americans.

Deputy Chief Robert W. Klotz said afterward that the operation "went very well. . . . It was just noisy and hot."

As the Iranians repeatedly chanted, 'stop police brutality," Klotz mumbled. 'I agree with that."

Many of the Iranians have claimed that police used indiscriminate force in arresting them during the July 27 demonstration, a charge that an internal police investigative arm is now probing.

But police restraint yesterday did not win praise from the Iranians. Bahram Nahidian, the Georgetown rug dealer who helped arrange the demonstration, shrugged his shoulders when asked to assess the police performance.

"I don't need their protection," Nahidian said. "I have no fear of any of this. . . . The maximum they can take is my life, and I am more than happy to do that for the cause of Islam."

For three hours the crowds exchanged taunts at an ever-increasing pitch, at times sounding like the cheering sections of archrival high schools at a football game.

"Long live Khomeini," chanted the Iranians. "Death to Khomeini," answered the Americans.

But when the Americans sang the Star Spangled Banner, as they did several times, the familiar schoolchild salute of hand-over-heart gave way to the skyward-pointed middle finger, a gesture aimed at the Iranians.

The tableau that produced the largest cheers occured when Larry Edwards, a 29-year-old Wheaton carpenter dressed in an Uncle Sam top hat and striped shirt, was boosted onto the shoulders of his buddies holding a mask of Khomeini, which he proceeded to lynch with a noose.

Yesterday's confrontation began at 11:30 a.m. at Dupont Circle. Before the march could begin police had to lift an American couple off the sidewalk, where they had blocked the path of the Iranians.

The marchers arrived in Lafayette Square half an hour later, where they abandoned plans to march on to the Justice Department and the National Press Club building.

Police then maneuvered the participants into four rings, with the Iranians inside, surrounded by the press, who were surrounded by police, on horse, motor scooters and foot, and finally, in the widest circle, were the Americans.

It all ended at 3 p.m., when the Iranians were escorted into three Metrobuses for a trip to the Islamic House. One officer wiped his brow, looked at a reporter, and said, "See you again tomorrow."

Two more pro-Khomeini groups had planned to demonstrate today. But one canceled its plans, and the second was reportedly reconsidering its plan to march from Lafayette Square to the State Department.