Ayatollah Ruhollah Khomeini has ordered a change in military tactics in the Persian Gulf war with Iraq that includes curtailing the number of large-scale offensives, a ranking official said yesterday.

"The imam had issued an overall order for a defensive holy war," Ali Reza Afshar, chief of staff of Iran's Revolutionary Guards, said in an interview with United Press International.

As part of the change in military strategy, Afshar said some units of the Iranian Army are now using "special techniques" similar to guerrilla warfare. He also said Khomeini has ordered fewer Iranian troops to take part in each offensive.

Iranian attacks since June 9 appeared to have been rapid, small-scale operations, sometimes capturing territory or destroying a few Iraqi military outposts before returning to base.

In Tehran, a car bomb exploded, injuring five people, the official Iranian news agency reported, adding that several people were arrested.

The Islamic Republic News Agency, monitored in Cyprus, said that although the explosion occurred during the afternoon siesta, crowds gathered in nearby streets and chanted slogans against the United States, Iraq and the Iranian underground group, the Mujahedeen.

In New York, the People's Mujahedeen Organization called The Associated Press to deny involvement in the explosion and to charge that the government was planting bombs to turn Iranians against the resistance.