Tens of thousands of Iranian demonstrators marched past the U.S. Embassy today shouting "Death to Carter" and other anti-American slogans to protest a U.S. revolutionary executions.

The demonstrations, organized by the Islamic Republican Party under Ayatollah Ruhollah Khomeini, coincided with the Moslem leader's strongest attack yet on liberal and leftist groups critical of the Islamic clergy's dominant political role in the new government.

The marchers were carefully controlled by Islamic Republican Party marshals and made no attempt to attack the embassy, which was protected by dozens of armed "Revolutionary Guards" loyal to Khomeini.

Some of the demonstrators shouted vehement slogans against the United States, President Carter and Israeli Prime Minister Menachem Begin. Among the chants were "Death to American," "Death to Carter" and "Death to Begin."

A witness reported that at least one American flag was burned. Another U.S. flag carried by the marchers was defaced with a large black cross over the stars and stripes.

Not to be outdone in "anti-imperialist" fervor, Iran's two main guerrilla organizations have scheduled their own demonstrations Friday against the Senate resolution. Other groups, including the Islamic Republican Party, also are expected to participate.

The slogan shouting seemed to be well orchestrated by "cheerleaders" riding in minibuses equipped with loudspeakers, observers said.

"The American Senate has become the supporter of killers," one slogan went.

Among the numerous banners carried by the protesters or draped across avenues was one in English that said, "The U.S. Senate is the house of War, corruption and unjustice." Another said, "We like the American people, we hate the American government."

There were no reports of any aggressive behaviour toward Americans who witnessed the demonstrations. In fact, the marchers generally did not seem terribly worked up about the U.S. policy they were protesting.

According to one witness passions only flared once when a crowd of Khomeini followers confronted a few hundred members of the Tudeh Communist Party in their midst who sat down on a street next to the embassy.

"Tudeh are parasites," the Islamic Republican Party followers chanted as the two groups exchanged angry shouts.

At a downtown square where speakers harangued demonstrators after the march, many people in the crowd ate popsicles hawked by vendors.

"It was far from an angry demonstration," a witness said.

Reflecting the official nature of the demonstration, three camera crews from the state-owned National Iranian Radio and Television were stationed in front of the embassy. A blue-and-White NIRT down so low that the draft from its rotors blew the chadors, or traditional full-lenght veils, off several women.

The speeches at the end of the march were not entirely anti-American. A representative of the Afghanistan Islamic Party read a message charging that the Soviet Union was flying Mig 21s and Mig 25s against Moslem Afghan rebels. The anti-Soviet statement also described Afghan President Nur Mohammed Taraki as an agent of the Soviet secret police, the KGB.

In a speech broadcast by the official radio, Khomeini condemned those who he said want to add the word "democratic" to the Islamic republic.

"If you see these people say 'republic' or 'democratic republic' or 'democratic Islamic republic' that would be what our enemies want," Khomeini said. "Our enemies don't fear a republic, they fear Islam."

Referring to the deposed shah, the ayatollah added, "Our enemy was not only Mohammed Reza Pahlavi. Everybody whose path is not the Islamic path is our enemy under any name whether he wants a 'republic' or a 'democratic republic.' Those who avoid using the word Islam are the enemy."

Khomeini also criticized Iranians who charge that the shah's one-man rule is being replaced with a "turbaned dictatorship." Apparently refering to followers of the late Ali Shariati, a popular anti-clerical Islamic writer, Khomeini said, "If they say Islam without the clergy, they do not believe in Islam."

In his speech Khomeini also appeared to attack the various secular parties that have sprung up during the revolution, even those that oppose the previous government.

The ayatolla further raised fears of a non-party dictatorship among liberal Iranians when he said, "It cannot be tolerated that they gather various people, find a name, hold meetings and then oppose Islam." He said of the members of such groups, "you should fight them more vigorously than you did the shah."