Iran tonight ordered all American journalists to leave the country, accusing them of "biased reporting" and paying undue attention to the hostages being held by militants at the U.S. Embassy.

Abol Ghassen Sadegh, the government's foreign press director, said American reporters will have to leave "as soon as it's possible. We're talking about a few days." He said the expulsion order applied to all American news organizations as well as individual journalists.

The Foreign Ministry also issued a blanket warning to all nations that joining the United States in economic penalties against Iran "would darken our relations with those countries." It reiterated threats to cut off oil exports to nations participating in sanctions.

The mass expulsion of more than a hundred American journalists, including press, radio and television, was ordered by Iran's ruling Revolutionary Council. The 13-member body had been considering the move for more than a week, since the government officially protested what it called racially biased and misguided reporting.

"All the correspondents from the United States should go from Iran and they will not be allowed to have activity here," Oil Minister, Ali Akbar Moinfar, a Revolutionary Council member, said.

The estimated 200 other Western journalists were not included in today's expulsion order but Moinfar, asked about them, replied, "If they do something against our nation and lie, they will go too." West German and British journalists were warned of expulsion last week, along with the Americans.

It was left unclear how promptly Iran expects the American journalists to leave. One, who asked foreign press chief Sadegh what would happen if he could not get an airplane ticket within 48 hours, was told by Sadegh, "We're not going to send you out on a camel."

Sadegh said that the "American media has been instrumental to a great extent in misinterpreting events and not presenting Iran in a fair light."

"There was too much stress on the hostages, not enough on the history of Iran," Sadegh said. "The (news) system works for the interest of the United States, not Iran."

Since foreign correspondents began flowing into Tehran after the Nov. 4 seizure of the American embassy, Iranian officials have repeatedly complained that Western reporters have concentrated unduly on the U.S. predicament and ignored what they consider the much greater past sufferings of Iranians under the rule of the deposed Shah Mohammed Reza Pahlavi.

The concept of the shah's alleged abuses of power is central to the Iranian hostage stance, maintaining as they do that the United States propped up a repressive regime and therefore shares responsibility both for the shah's "crimes" and his return to Iran to stand trial. Until then, they say, the hostages will be held.

Although reporters received occasional scoldings, Iranian authorities have only banished correspondents twice since the Nov. 4 occupation of the U.S. Embassy -- Time magazine's bureau and an Associated Press newsman -- charging that their stories defamed the nation's Islamic ruler, Ayatollah Ruhollah Khomeini.

Then a week ago, officials started threatening expulsion and restricting some correspondents, citing as their justification two other Khomeini stories -- a CBS television report from Washington saying Khomeini was cut off from vital information and a Time cover story naming him the "Man of the Year" and saying he "roused hatred in nations."

Reprisals followed in quick fashion. CBS was indefinitely denied the right to transmit its stories through the national television network. NBC television videotapes of anti-Khomeini demonstrations in the holy city of Qom were confiscated by police, Iran refused to grant visas for arriving journalists.

Press crackdowns intensified in recent days with NBC denied transmission rights, reporters rounded up in the troubled northwest city of Tabriz and finally yesterday officially barred from the town by Governor General Nooroddin Gharavi, who blamed foreign reporters for sparking the violence.

Recent hostile treatment of the media capped by tonight's mass expulsion coincides with a highly sensitive period for Iranian authorities, who are squeezed by the threat of economic sanctions from abroad and spreading provincial rebellions at home.

Foreign Minister Sadegh Ghotbzadeh, who as former head of the national television and radio network understands the workings of the press, lashed out at the Western media today.

Asked by an Iranian newsman if it was true that Iran was ready to negotiate release of the hostages, Ghotbzadeh replied:

"This is not true at all. As you know, the international news agencies distort the truth under influence of dirty Zionists and unfortunately some international news media say things which give an upside-down impression of matters."

In the wake of the Soviet veto Sunday night, they blocked a U.N. Security Council resolution for economic sanctions against Iran, Ghotbzadeh's ministry issued a stern warning today to nations that might participate in a U.S.-sponsored trade embargo or possible blockade.

"Now that the obstinate and baseless U.S. attempts have been defeated," the ministry statement said, "we insistently ask other countries not to get involved in the political games of the U.S. and to avoid any action that would darken our relations with them."

In a more pointed warning, the ministry said that neighboring countries allied with the United States risk violating Iran's "vital interest" if they help in a blockade of the strategic Strait of Hormuz, located at the entrance of the Persian Gulf.

In another development, four black American ministers led by the Rev. Gene A. Moore met with the militants holding the hostages at the U.S. Embassy. The ministers, all from Houston, reportedly discussed with the captors the possibility of holding a religious service for the hostages on Tuesday, the birthday of the late Martin Luther King.

It remained unclear, however, whether the service would be held.