While the CIA interdicted arms, the NSC moved in to persuade the Salvadoran government to hold early elections in a bid to persuade a balky U.S. Congress to pass military aid for the Salvadoran armed forces.

The White House dispatched North and conservative former Sen. Richard Stone, D-Fla., to El Salvador in March 1983 to persuade provisional President Alvaro Magana to advance presidential elections from March 1984 to December 1983.

Magana agreed to change the election date. But the operation's cover was blown when a Tampa television reporter overheard their conversations on the plane returning to the United States.

"When I identified myself as a reporter, North was really upset, " the reporter, Mark Feldstein, said Friday in Washington, where he is now working for a local station. "He pointed a finger at me and said, 'If you really love your country, you won't broadcast this.' "

Even though Magana had agreed to the earlier date, the election ultimately was held in March 1984 because of the government's inability to get it organized by December 1983. During the campaign, the CIA reportedly helped fund the successful presidential bid of Christian Democrat Jose Napoleon Duarte.

In 1985, the NSC and CIA joined to sponsor a media operation designed to influence the internal and international press coverage of El Salvador. The objective was to change the image of El Salvador from that of a war-torn country to that of one where peace was gradually returning.

The CIA reportedly provided funds for the campaign through a Venezuelan public relations company, while the NSC assisted the effort through its so-called Office of Public Diplomacy. It is located within the State Department but partly overseen by North.

* The United States: Through the Office of Public Diplomacy, the NSC conducted a three-year propaganda campaign to influence U.S. media coverage of Central America, including "leaks" to selected reporters that reflected negatively on Nicaragua and positively on El Salvador.

Initially, the effort focused on El Salvador, but it shifted to Nicaragua after Congress in 1984 dropped restrictions on military aid to the Salvadorans.

When Congress also quit opposing contra aid last summer, the White House shut down the operation and turned the office over to the State Department.

Over the past three years, the CIA, the FBI and the National Security Agency also have cooperated in an operation aimed at monitoring the activities of U.S.-based opponents of Reagan's Central America policies. They have concentrated particularly on those involved in the so-called sanctuary movement, which aids refugees from El Salvador and Guatemala.

The CIA did not participate directly in the surveillance, but sources say it provided "support" information to the FBI.

In other cases, FBI agents have interviewed hundreds of Americans who have visited Nicaragua.

Intelligence sources say the surveillance of groups that shelter Central American refugees is aimed at preventing terrorists from infiltrating the United States among the refugees. Interviews with the Americans returning from Nicaragua is an effort to learn what influence the Sandinistas may have on U.S. dissidents.

ABORTED OPERATIONS

Besides these operations, the Reagan administration has aborted -- or debated but never implemented -- a number of other programs in Suriname, Lebanon and Mexico, sources said.

In June 1983, CIA briefers advised Congress that Reagan had authorized a plan to undermine the leftist government of Surinamese military leader Desi Bouterse. The intelligence committees objected to the plan; the CIA dropped it.

In 1983 and 1984, NSC officials proposed a covert program against Mexico to persuade it to change policies favoring Nicaragua and leftist Salvadoran rebels, intelligence sources said. The proposal entailed trade sanctions and funding for opposition groups.

But the proposal was never implemented, sources said, because "cooler" heads prevailed by arguing that U.S. national security would be harmed if Mexico were destabilized.

Meanwhile, planning for future covert actions continues.

Congressional sources say there is debate within the administration about providing aid to rebel forces in Mozambique and Ethiopia.

The sources also said that, while no planning had begun, some hard-line officials have discussed the possibility of giving funds to Vietnamese exiles to create an anti-Hanoi rebel movement.

Cuban exiles in Miami have asked the White House for aid to resume paramilitary actions against Fidel Castro. In March, veterans of the failed CIA-organized 1961 Bay of Pigs invasion published in The Miami Herald an open letter requesting aid to "fight for the liberation of Cuba."

An administration source said that, while the White House is sympathetic to the exiles' wishes, it has decided to focus its efforts on Nicaragua.

But the possibility of funding for a covert program in Cuba has not been foreclosed. "Cuba could well be next after Nicaragua, " one official said recently.