Philippine President Ferdinand Marcos reacted angrily today to American press reports that his World War II exploits were fabricated, attributing the charges to a "smear campaign" by his political opponents and urging guerrilla veterans here to prove them wrong.

Marcos was responding to a New York Times report today quoting U.S. Army records as showing that American officers had rejected Marcos' requests for recognition of his guerrilla unit after the war. The paper said the officers called Marcos' claims about the activities of his Ang Manga Maharlika (The Nobles) unit "absurd," "fraudulent" and "preposterous."

Marcos long has made political capital of his alleged war record, for which he was awarded 27, 28, 32 or 33 medals, according to various Philippine government reports, making him the Philippines' most decorated soldier of World War II. Serious questions also have been raised about whether he was actually awarded the medals.

The issue of the veracity of Marcos' war record and his medals is an especially sensitive one with the ailing Philippine leader. In 1982 he ordered the newspaper We Forum shut down and its editor and nine staffers arrested and tried on subversion charges after the paper published a series of articles disputing Marcos' exploits. The charges were dropped last year, but a libel case is still pending.

In his current campaign for reelection in a presidential poll set for Feb. 7, Marcos repeatedly has referred to his alleged war record and wounds in speeches to various audiences. Addressing a rally in a Manila slum area today, Marcos struck the familiar theme anew.

"They say I limp because I am sick and dying," he told about 40,000 people in the Tondo slum development project. "I limp because I got wounded on my left knee during the war. They laugh, because they never knew what it was to be wounded."

In what a presidential press statement called his "strongest tirade against the opposition in the current campaign," Marcos blamed his political foes for the allegations about his war record but gave no evidence that they were behind the American news reports.

Opposition figures "who collaborated with the enemy have no right to question the role of the country's guerrillas during the war," Marcos told the Tondo crowd, according to the presidential statement.

The Marcos retort apparently referred to opposition vice presidential candidate Salvador Laurel, whose father, Jose P. Laurel, served as the Philippines' president under the Japanese occupation.

"You who are in Tondo and fought under me and who were part of my guerrilla organization, you answer them," the statement quoted Marcos as saying.