The federal government filed an urgent appeal last night of Friday's U.S. District Court ruling that permits a demonstration here Tuesday related to the events in Iran.

The government asked that an expedited hearing and decision be provided before the demonstration scheduled Tuesday by a group of American and possibly Iranian students who say they want to march to promote peace and understanding between citizens of the two nations. At least part of the demonstration is planned for the White House and Lafayette Square areas.

In a brief filed with the U.S. Court of Appeals here, the Justice Department asserted that Judge Aubrey Robinson failed to apply the "clear and present danger" test in rejecting the government's effort to ban the demonstration.

Permits for demonstrations may be denied, the government argued, if "it reasonably appears that the proposed public gathering will present a clear and present danger to the public safety, good order or health."

The government contended that the danger in this instance is to the hostages at the U.S. Embassy in Tehran, who, according to a State Department official, might suffer retaliation for any violence directed against the demonstrators here.

In his Friday ruling, Robinson asserted that the government had failed to show a sufficient link between events that might arise here and those that might follow in Iran.

Without a "very substantial" showing of "inevitable direct and irreparable harm" to the hostages, Robinson said, banning the march is not justified.

There was no word on when a hearing might be scheduled.