The Reagan administration's secret overtures and arms shipments to Iran are part of a seven-year-long pattern of covert Central Intelligence Agency operations -- some dating back to the Carter administration -- that were designed both to curry favor with the regime of Ayatollah Ruhollah Khomeini and support Iranian exiles who seek to overthrow it, according to informed sources.

In 1983, for example, the CIA participated in a secret operation to provide a list of Soviet KGB agents and collaborators operating in Iran to the Khomeini regime, which then executed up to 200 suspects and closed down the communist Tudeh party in Iran, actions that dealt a major blow to KGB operations and Soviet influence there, the sources said. Khomeini also expelled 18 Soviet diplomats, imprisoned the Tudeh party leaders and publicly thanked God for "the miracle" leading to the arrests of the "treasonous leaders."

At the same time, secret presidential intelligence orders, called "findings," authorized the CIA to support Iranian exiles opposed to the Khomeini regime, the sources said. These included providing nearly $ 6 million to the main Iranian exile movement, financing an anti-Khomeini exile group radio station in Egypt and supplying a miniaturized television transmitter for an 11-minute clandestine broadcast to Iran two months ago by Reza Pahlavi, the son of the late Shah Mohammad Reza Pahlavi, who vowed, "I will return."

One well-placed intelligence source said that this support of the anti-Khomeini exile movement is "just one level above [intelligence] collection," and that the money involved was equivalent to the "walking-around money" frequently distributed in American political campaigns. Administration officials stressed that the CIA operations are not intended to bring about Khomeini's downfall but are aimed primarily at obtaining intelligence about his regime through the exile groups.

The White House and administration spokesmen declined to comment on these CIA operations. Vice Adm. John M. Poindexter, the president's national security affairs adviser, told a television interviewer Sunday that "I don't want to confirm or deny any other operations" and added that "we aren't seeking the overthrow of the Khomeini regime."

Press and broadcast reports from Iran have repreatedly accused the U.S. government of backing anti-Khomeini exile activities. Informed sources said that the Khomeini regime knows many of the details of the CIA operations because it has agents inside the Iranian exile groups.

Some of the Iranian exiles in Paris said it is well-known within their groups that they have received CIA money. Sources also said that some of the CIA money was used to speculate in currency markets in Switzerland.

Administration sources said that all CIA programs concerning Iran have been designed with several objectives: to build bridges to potential Iranian leaders, to use the exiles for information about what is happening in Iran, to develop independent intelligence sources, to win friends, to diminish Soviet influence and to keep pressure on the Khomeini regime by demonstrating that the exile and dissident opposition is active.

Iran is strategically vital because of its oil supplies, warm-water ports on the Persian Gulf and proximity to the Soviet Union. Iran's political turbulence and the possibility that one of the exile groups could some day assume power justifies a U.S. strategy that proceeds on several tracks, according to several administration officials, and that view is shared by some former U.S. intelligence officers.

"I have no knowledge that the Reagan administration is giving money to the Iranian exile groups, but I see no reason not to give them money and at the same time extend a hand to Khomeini," Stansfield Turner, CIA director in the Carter administration, said Monday. "Playing both sides of the fence is not unusual, as long as they did not fund any exile group to the extent that they would try to overthrow the [Khomeini] government. There is not a prayer that they could do that."

But one well-placed administration source said the CIA operations involving Iran were ad hoc and inconsistent, rather than being the result of a coherent U.S. strategy. "The U.S. does not have a policy but a series of actions," said the source, who described the administration as "groping in a maze" on the Iran issue.

Despite the CIA efforts to curry favor with the Khomeini regime, Iran continued to encourage violence against American interests, sources noted. For example, intelligence shows that Iran directly supported the October 1983 bombing of the Marine Corps barracks in Beirut in which 241 U.S. servicemen were killed. This was less than a year after the CIA received a list of KGB agents in Iran from a Soviet defector and gave the names to the Khomeini regime. Sources said that the British intelligence service also participated in the operation that revealed the Soviet agents in Iran.

Administration officials said that more recent overtures made under President Reagan to "moderates" in Tehran have stopped Iranian government sponsorship of terrorist actions against Americans.

In January 1981, when Reagan took office and 52 Americans returned after 444 days' captivity in Tehran, the CIA had already begun under President Carter a number of anti-Khomeini operations. One was designed to gather intelligence about Iran and support Iranian exiles, sources said; another was a more ambitious plan that one senior source said was designed to inflict "punishment" on the Khomeini regime, which was holding the U.S. hostages.

Under Reagan and his CIA director, William J. Casey, the first major Iranian operation was intended to support an exile group headed by the shah's former naval commander-in-chief, Rear Adm. Ahmad Madani. The Madani group received several Sources said that the Khomeini regime knows many of the details of CIA operations.

million dollars, but proved too independent by insisting on control of their own anti-Khomeini operations, and the CIA connections were soon dissolved.

In 1982, the CIA began supporting the main Iranian exile movement, the Paris-based Front for the Liberation of Iran (FLI). Headed by former prime minister Ali Amini, the FLI advocates Khomeini's ouster and since 1983 has called for restoration of the Iranian monarchy.

The CIA has given the FLI $ 100,000 a month. But beginning about two years ago, two members of the National Security Council staff, Lt. Col. Oliver North Jr. and Vincent M. Canistraro, became involved in supervising the CIA operation after hearing allegations that the FLI was mismanaged and ineffective.

The allegations included charges that some FLI members were providing useless and questionable information to the CIA and that CIA funds were being used to speculate in currency markets in Switzerland. Consequently, the FLI member functioning as liaison with the CIA was ousted in 1985. His successor, however, was discovered to be a former communist who advocated hostage-taking and who was a suspected Khomeini informer, according to U.S. and Iranian sources.

That liaison was removed earlier this year, and the CIA appointed one of the shah's former cabinet officers as the new overseer of the FLI money, the sources said.

Neither the CIA nor the White House ever seriously believed that exile groups were strong enough to overthrow Khomeini, sources said, and none of the current operations includes paramilitary support.

As part of the FLI support, the CIA also provides equipment and $ 20,000 to $ 30,000 a month for the organization's Radio Nejat, or Radio Liberation, which broadcasts anti-Khomeini programs for four hours a day from Egypt to Iran, according to U.S. and Iranian sources.

As the links to the exile groups were being built, the CIA received an unexpected windfall of intelligence information in Iran through the defection of Vladimir Kuzichkin, a senior KGB officer in Tehran whose job it had been to maintain contacts with the Tudeh party. Kuzichkin defected to the British in late 1982 and was debriefed later by the CIA, giving the United States details of Soviet and Tudeh operations in Iran.

The CIA then provided Khomeini with lists and supporting details of at least 100 and perhaps as many as 200 Soviet agents in Iran, sources said. After arresting and executing most of the alleged agents, Khomeini outlawed the Tudeh party on May 4, 1983, and expelled the 18 Soviet diplomats believed to be involved in KGB operations. Many Tudeh members were arrested, including the party's secretary general and six central committee members, and they were forced to make televised confessions that they spied for Moscow.

One well-placed source said the CIA action was intended to cripple KGB operations in Iran while offering "a gesture of good will" to Khomeini.

There were reports at the time of an upheaval in the Tudeh party, but it was not known that the CIA had a role. The role of Kuzichkin also passed largely unnoticed except for a 1985 column by Jack Anderson and Dale Van Atta reporting that the defector had brought with him two trunks full of documents about the KGB and the Iranian communist party. The column reported that the British "secretly turned the information over to Khomeini."

A CIA memo of May 17, 1985, saying that the United States was lagging behind the Soviets in cultivating Iranian contacts for a post-Khomeini era, was apparently one of the first actions that led to Reagan's decision to begin secret overtures to the Iranians and eventually to ship them arms this year.

A recent CIA-supported operation was the sudden appearance on Iranian television two months ago of Reza Pahlavi, son of the late shah. That clandestine anti-Khomeini broadcast was made possible by the CIA, which provided technical assistance and a miniaturized suitcase transmitter, the sources said. The broadcast disrupted two channels of Iranian television for 11 minutes at 9 p.m. on Sept. 5. It is not known whether the shah's son knew that the CIA had provided support for the broadcast.

The Khomeini regime apparently was aware of or suspected a U.S. role in the clandestine appearance and responded with a radio broadcast of its own, declaring that "the terrorist government of Reagan . . . in a disgraceful manner was the vanguard of this puppet show."Staff researchers Barbara Feinman and Ferman Patterson contributed to this report.