May 27, 1982

Secretary of State Alexander M. Haig Jr. said today that the United States would play ''a more active role'' in coming weeks in trying to end the Iraqi-Iranian war. He seemed to warn Iran that if it spread the conflict into neighboring nations Washington would protect its ''vital interests'' in the Persian Gulf. In the Administration's first comprehensive Middle East policy statement, Mr. Haig discussed at length the Iraqi-Iranian war, the stalemated Egyptian-Israeli negotiations on Palestinian self-rule and the Lebanon crisis. In connection with the Egyptian-I@sraeli talks, Mr. Haig said there should be a ''redoubling of efforts.'' Administration officials said that the United States had raised the possibility of a three-way meeting involving President Reagan, President Hosni Mubarak and Prime Minister Menachem Begin next month but that nothing had been set.

An article about Brentano's Inc. in Business Day yesterday incorrectly reported the amount owed by the book chain to the Ingram Book Company. It is $277,000.

''My days of stay in Great Britain will still be an incessant prayer in favor of peace, raised together with all God's people, who carry sculptured in their hearts the words of Christ: 'Blessed are the peacemakers, because they will be called the sons of God.' '' - Pope John Paul, in letter to President Leopoldo Galtieri of Argentina. (A18:4.)

The Justice Department filed suit today to force the Tribune Company of Chicago to sell five Florida publications that it acquired in 1980, an antitrust challenge that seems likely to have wide repercussions in the newspaper industry. Acquisition of the five papers, all of them weeklies published and distributed in Osceola County near Orlando, was said by the Government to have lessened substantially or to have eliminated competition for local advertising, in violation of the Clayton Act barring anticompetitive mergers. The Sentinal Star Company, a Tribune Company subsidiary based in Orlando, which publishes the city's only daily newspaper, was also named as a defendant. The subsidiary bought the smaller papers for $4.14 million.

AS children are increasingly exposed to images of nuclear war on television and in print, parents, teachers and mental-health professionals are being confronted with the psychological effects of those images. Some typical fears of young people were expressed at a recent meeting of Future Generations, a new youth organization in New York that opposes the nuclear-arms buildup. Susan Markowitz, a 12-year-old student at the Bank Street School, was talking about the first time she became aware of the possibility of nuclear war. ''At the beginning of this year when the class started reading articles,'' she said, ''I got very frightened that the world could blow up.'' Rachel Dretzin, 16, who goes to the Dalton School, said she thought her schoolwork had been suffering lately and said she frequently had nightmares. ''Last week I dreamed that a bomb went off in my kitchen and there were bombs all over the house,'' she said. ''When I walk in the street, I look at things and imagine what would happen if they just disappeared.''