The report of the congressional inquiry into the Iran-contra affair portrays President Reagan as actively attempting to conceal key aspects of the scandal from the American people last fall and documents an intense effort within the administration to cover up possibly illegal actions by the president and his subordinates.

In particular, the report says, Reagan and his aides went to unusual lengths to conceal the president's role in the 1985 shipment of 18 Hawk antiaircraft missiles to Iran through Israel as part of an effort to win freedom for American hostages in Lebanon. This shipment was sensitive because it occurred before Reagan had signed a legal authorization for such weapons transfers, according to the report. Reagan aides fabricated chronologies to disguise the facts of the shipment, and some White House officials withheld details from others, the report said.

Reagan is described in the report as being at the forefront of those who misled the nation last fall.

"The president himself told the public that the U.S. government had no connection to the Hasenfus airplane," the report says, referring to the plane used in resupplying the contras that Nicaragua shot down, leading to the capture of cargo handler Eugene Hasenfus. "{Reagan} told the public that early reports of arms sales for hostages had 'no foundation.' He told the public that the United States had not traded arms for hostages. He told the public that the United States had not condoned the arms sales by Israel to Iran, when in fact he had approved them and signed a finding, later destroyed by {Vice Adm. John M.} Poindexter, recording his approval."

"All of these statements by the president were wrong," the report said.

Last summer, when internal White House notes were made public that suggested Reagan had actively been part of the effort to conceal information in this time period, the White House spokesman, Marlin Fitzwater, accused "some members of the press" of attempting to "destroy" Reagan over the Iran-contra affair. He defended Reagan's efforts to conceal information on grounds that lives of the hostages were at stake, and he noted that the Tower special review board had concluded that Reagan did not intend to mislead the American public.

In their minority report also made public yesterday, eight Republicans assert, "There is no evidence that the president directed, encouraged, or in any way condoned this cover-up . . . . "

But the majority report revives the picture of Reagan as leading the effort to hide information. He told congressional leaders last Nov. 10 that no laws had been broken, no ransom paid for hostages, and no officials or agencies within the U.S. government bypassed. All these assertions have been subsequently called into question.

In his Nov. 13 nationally televised address, Reagan "committed himself categorically to the proposition that there had been no trade of arms for the hostages and no violations of law," the report says. "Certain members of the NSC {National Security Council} staff and of the CIA, in turn, committed themselves to creating a version of the facts for internal and public consumption that would sustain this proposition."

On the contra resupply effort, the report found "no direct evidence" that Reagan was a "knowing participant" in the effort to mislead Congress and the nation. Still, the report said that "the president's actions and statements contributed to the deception."

On Iran, however, the report says Reagan knowingly made untrue statements. For example, in his Nov. 19 news conference, Reagan said the United States had not condoned any arms sales to Iran prior to his signing of a "finding" on Jan. 17, 1986. However, the congressional report points out, Reagan had told Secretary of State George P. Shultz earlier that same day that he had known of the Hawk missile shipment, which was made before any finding was signed.

The report says former national security advisers Robert C. McFarlane and Poindexter, former NSC staffer Lt. Col. Oliver L. North and the late director of central intelligence William J. Casey were among those "engaged in a deliberate attempt to falsify the facts" about the Hawk missile shipment.

"All of this was not the result of any memory lapse," the report says of the false chronologies. "The consequences of this exercise in falsifying the facts were severe. As North testified, by creating an erroneous version of the facts in the chronologies, those responsible were 'committing the president of the United States to a false story.' "

Reagan stuck with aspects of the false story two months later when he was interviewed by the Tower review board. According to that report, Reagan at first said he did not remember how the Hawk shipment came about but that he objected to it, and later Reagan changed his story to say he could remember nothing about it.

Concern over the legality of the Hawk missile shipment was at the center of an internal White House struggle, according to the report. On the day before Reagan's Nov. 19 news conference, top lawyers from the various intelligence and national security agencies met at the office of then-White House counsel Peter Wallison, the report says.

At this meeting, they quizzed Navy Cmdr. Paul Thompson, who was then general counsel to the NSC, about the Iran arms deals. Thompson refused to tell them details, saying he was under orders from Poindexter to keep information from them. State Department counselor Abraham Sofaer told Wallison this was "extremely serious," according to the report.

In responding to the congressional report yesterday, Fitzwater took a conciliatory approach, saying the document confirmed Reagan's statement that he did not know about the diversion of money to the contras and that Reagan had accepted responsibility for mistakes. "This report is but another step in the investigatory process," he said, "but it does culminate the long summer of self-examination for America and for the administration and now we are through it, we are moving on and we trust that out of this experience has come a new wisdom about the process of governing America."Staff researcher Michelle Hall contributed to this report.