About 40 Muslims carrying banners quoting Ayatollah Ruhollah Khomeini and chanting Islamic slogans marched through downtown Washington yesterday to protest what they called the "oppression of Islam" by the news media and the Justice Department.

The marchers began their walk outside an Islamic center on upper 14th Street, stopped briefly in front of the Washington Post building at 15th and L Streets NW to object to newspaper coverage and then went to the front entrance of the Justice Department at 10th Street and Pennsylvania Avenue. e

Police in riot helmets lined doorways as a befuddled lunchtime crowd of government workers looked on, but there were no incidents during the march.

Dawud Abdullah, one of the organizers of the protest, said the march was intended to show the unity of "Muslims of all races in the Washington community" and to protest the indictment of three persons believed to be Muslims in connection with the July slaying of Iranian exile leader Ali Akbar Tabatabai, an arch-critic of Khomeini.

After the rally at the Justice Department, which lasted for about 40 minutes, the demonstrators proceeded to the Washington Monument for two hours of prayer.

Asked why so few turned out for the demonstration -- thousands of persons had taken part in earlier protests -- a group spokesman, who identified himself only as Saleem, said "this was really a spur-of-the-moment-type situation . . . not a lot of people knew.

"Plus," he said, "we have a lot of poor and oppressed brothers and sisters who have to work during the day and couldn't get the time off."