Ayatollah Ruhollah Khomeini accused the United States today of trying to distract world attention from its "crimes against Iran" but a Khomeini aide and former foreign minister said the real reason for seizure of the U.S. embassy was a move to "mobilize the masses" to improve the coutry's economy.

Khomeini, speaking in the holy city of Qom, said the United States was "trying to create amusements" to "prevent us from bringing to the notice of the world the documents and evidence of crimes and plunder of the presidents of the United States and, in particular, the present one."

The remarks, published by the official Pars news agency, did not explain what Khomeini meant by "amusements" but he apparently was referring to U.S. moves to put the dispute before the United Nations and the International Court of Justice.

In an interview published by the English-languate weekly The Iranian, former foreign minister Ibrahim Yazdi gave an explanation for the seizure of the U.S. embassy and the continued holding of 50 hostages that coincide with the suspicions of many Western observers.

"In order to rally the masses, this kind of thing should continue," Yazdi was quoted as saying.

"If this campaign against the Americans ends just by a trial of these Americans and their deportation, it will be a disaster. It has to go further. We have to divert this to the reconstruction of the country. When the masses are completely movilized against the Americans, it is easier to tell them to go to the fields and do this and that," he said.

He added, "If one is to mobilize themasses and to correct their attitudes toward a consumer society, you have to have a very strong motivating force."

Yazdi, who lived in exile in the United States 14 years, resigned as foreign minister two days after the American embassy was seized Nov. 4 but he is still an aide of Khomeini and has been named to head an investigation of problems in Iran's provinces.

Iran's leading revolutionary judge, Ayatollah Sadegh Khalkhali, who has sentenced hundreds of supportors of the deposed shah to death by firing squad, told reporters in Qom that none of the Americans hostages will be sentenced to death if they are tried as spies.

It was unclear what authority Khalkhali's remarks had. In the past, declarations about the hostages by various officials have often been rejected by the militant students holding the embassy or by Khomeini.

Meanwhile, the Foreign Ministry said that a letter purportedly written by Sen. Edward M. Kennedy (D-Mass.) asking to visit Khomeini and pledging support for him apparently was a hoax.

Kennedy's office in Washington said that Kennedy had had "no contact whatsoever with anyone in the Iranian government, especially a letter being sent to the ayatollah."

Before the Foreign Ministry's denial of the letter's authenticity, official Radio Teharan had broadcast its contents several times including a purported Kennedy pledge that "I will give my blood for you." There was no indication where the letter originated.

Kennedy, a Democratic presidential candidate, recently stirred controversy in the United States and received front-page press coverage in Iran for remarks condemning the shah as a dictator.