Federal law enforcement agents posted notices yesterday that officially closed the downtown shelter for the homeless operated by the Community for Creative Non-Violence, but there was no move to evict the more than 600 persons who continued to occupy the building.

At the same time, William F. Madison, General Services Administration regional administrator, said CCNV leader Mitch Snyder's vows that shelter residents would barricade themselves inside the building at 425 Second St. NW increased the "probability of injuries" to residents. Officials asked Snyder to "encourage voluntary departure" from the structure.

Snyder dismissed Madison's plea, included in a hand-delivered letter, as "just another public relations device," and said the GSA had known for 18 months about the fire and safety violations that Madison cited as the reason for ordering the building vacated.

By last night, few of the homeless persons who were inside shelter when the notices were posted had left voluntarily, and at least two CCNV workers with walkie-talkies were standing guard outside the building with orders from Snyder to bolt the doors if police arrived to shut it down.

About 6:15 p.m., members of the Hotel and Restaurant Employees Union, Local 25, delivered food left over from a union party. Ron Richards, a union spokesman, said the group would continue to deliver food as long as the shelter remains open.

A three-judge panel of the U.S. Court of Appeals ruled earlier this week that the shelter, which the federal government has been trying to close for more than four months, could be shut down after noon yesterday.

Agents of the GSA's Federal Protective Service arrived at the building about 4 p.m. to post the notices, which warned that persons who did not leave would be "subject to prosecution or removal."

"I don't think we're bound at all by what that piece of paper says," Snyder said of the notice. "We're bound by the fact that there are 600 people here who have nowhere else to go."

Snyder has insisted there are no other available shelter beds for the people housed at the complex, but the appeals court held that a new men's shelter in Anacostia and a new women's shelter in Northwest are adequate to fulfill the federal government's responsibilities for providing protection for the city's homeless.

The situation at the shelter remained tense and confused as residents feared police action against them. Residents and staff members expressed fear that phone service and electricity would be cut off, and at least one gas-powered electric generator was readied for use.

Throughout the building, the former classrooms and offices of the old Federal City College were filled with cots, mattresses, blankets and the personal belongings of the people who continued to live at the shelter.

Federal officials now contend that conditions inside the shelter include "life-threatening" fire and safety violations, according to the letter sent to Snyder by the GSA. The letter stated that the "deficiencies" include stairwell fire doors that are padlocked, outside doors that are welded shut, blocked windows and flammable debris throughout the building.

Snyder has maintained that the shelter is still better that the streets.

As a way of publicizing the plight of the homeless, his group attempted to have a sculpture of a man, woman and child huddled over a steam grate included in the National Park Service's "Pageant of Peace" that opened last night on the Ellipse.

The group's request was turned down by the park service and on appeal to U.S. District Court here, and CCNV declined to place the sculpture nearby. When the pageant opened last night, CCNV staff members displayed a photo of the sculpture with "censored" printed over it.

As night fell, residents of the shelter returning from a day on the streets or from jobs streamed past the notice posted on the front door, returning to their rooms almost as if nothing had happened.

Some residents talked about what they might do if federal officials try to remove them.

"I'm going to leave here when they ask us to go," said Jeffrey Jones, a 28-year-old migrant farm worker from North Carolina who said he had been living at the shelter for past months. "I like this place. It's one of the best shelters I've been in," Jones said. "But our time is up. I don't want to go to jail."

Sylvester Dean, 36, a convicted burglar who keeps an electric leaf blower in his room and scouts the neighborhoods for odd jobs clearing lawns, echoed Snyder's sentiments.

"If they close this building, where are we going to go?" asked Dean. "We are going to be in the streets." Staff writers John Ward Anderson, Lawrence Feinberg and Anne Simpson contributed to this report.