Iranian authorities today released another purported American document -- allegedly a confidential memo on White House stationery from President Carter's national security adviser, Zbigniew Brzezinski, to then-secretary of state Cyrus Vance -- designed to show America's continued attempts to interfere in Iran's internal affairs.

The four-paragraph, single-spaced memo, dated Aug. 6, 1979, said President Carter wants "to exploit the climate of suspicion and mistrust that exists between Iran and its neighbor's -- presumably Iraq and the Soviet Union -- to weaken the foreign policy positions of the new government here.

[In Washington, deputy White House press secretary Rex Granum called the document an "utter fabrication." He said the alleged memo had surfaced in late April, that the White House had denied its authenticity then, and added, "It's no more true now" than it was then.]

The purported memo said the American policies should take "into consideration the views expressed by the shah of Iran during recent consultations."

The Iranians have maintained that the deposed shah, who was forced to flee Iran in January 1979 as a result of violent demonstrations against his regime, still influences U.S. policy, which they say is aimed at overthrowing the new Islamic republic here.

The alleged Brzezinski-to-Vance memorandum, marked "confidential," was reported to have been found in the U.S. Embassy here by militant students who occupied it Nov. 4. Photocopies of the memo were distributed to reporters today at an Iranian government-sponsored conference aimed at detailing alleged illegal intervention by the United States in Iranian affairs in the last 27 years.

According to the document distributed today, President Carter wanted American diplomats here "to establish contacts with leaders of all political trends and organizations, without exception, including the minorities and the extremist groups, which are able to provoke armed uprisings against [Ayatollah Ruhollah] Khomeini's regime."

While these diplomatic activities could be seen as a normal attempt to maintain contact with all elements of the Iranian political spectrum -- something the United States was accused of not doing during the reign of the shah -- the reference to the extremist group is viewed by the current Iranian government as an attempt to stir up trouble for the Islamic republic.

Iran currently faces an armed uprising in Kurdistan, and there have been antigovernment activities during the last six months in Baluchistan, Azerbaijan and Khuzestan, where residents want more autonomy from central government rule.

Adding to suspicions among the Iranians here is the presidential directive supposedly quoted by Brzezinski against establishing contacts with religious leaders, politicians or members of the opposition "without prior consultation with the director of Central Intelligence."

The CIA was responsible in 1953 for overthrowing the nationalist government of Mohammed Mossadegh and returning the shah to power here.