A small group of American and Iranian students carrying carnations and signs saying "Violence Is No Answer," marched through downtown Washington yesterday for a "peaceful solution to the Iranian crisis. A small group of angry counterdemonstrators, meanwhile, marched alongside them waving American flags and shouting, "Get the hell out."

Lunchtime crowds gathered to watch as the two groups wound their way down K Street, Connecticut Avenue and Massachusetts Avenue toward the Iranian Embassy, separated by a wall of dozens of police motor scooters. But, unlike two weeks ago, when American office workers poured out of their buildings to heckle Iranian demonstrators, few in the crowd of onlookers joined in either march.

At any time, the students demonstrating numbered only about 30, including a dozen Iranians. The counterdemonstrators started out with a dozen and grew to about 15 along the way.

The parallel demonstrations began shortly before noon in McPherson Square, the site two weeks ago of a bitter clash between Iranian students who supported the Ayatollah Ruhollah Khomeini and American citizens angered by the take-over of the U.S. Embassy in Tehran.

On one side of the park, Frank Jackalone, chairman of the U.S. Student Association, was gathering his demonstrators and calling the event a "symbolic expression that Iranians and Americans can work together . . . We're concerned that there's been too much hostility on college campuses."

On the other side, a group of American demonstrators who described themselves as construction workers, house painters and plumbers, paraded before television cameras with placards that contained obscene graphics.