Prince George's County officials and union leaders negotiated for eight hours yesterday without resolving the county's week-long public employes' strike.

Some progress was reported in the talks, which were called by federal mediator Brian K. Flores. But Flores broke off the session shortly before 10 p.m., saying that the county and leaders of the five locals of the American Federation of State, County and Municipal Employees "were no longer moving forward on the issues. I felt we were losing ground."

The mediator said he would contact the sides this morning in an effort to bring them back to the negotiating table before Monday.

The county and the union were able to agree yesterday on two of the three contract issues in dispute, all of which relate to union prerogatives. Economic issues had been agreed upon previously.

Union leaders dropped their demand for a full time, paid shop steward, and the two sides agreed to 75 days of paid county leave for union personnel to attend meetings and conferences. The union had wanted 126 days and County Executive Lawrence J. Hogan had offered 46.

Yesterday's talk foundered on one other contract issue and two related to the strike itself, which began at 12:01 a.m. Tuesday.

The union is demanding, and the county refusing to grant, a closed-shop arrangement under which union membership would be a condition of employment.

The 1,500-member union is also demanding amnesty for 120 guards at the county jail who have been off the job since the strike started. Sixteen members of the jail's night shift walked out Tuesday morning despite a court order prohibiting them from doing so. Hogan has fired them and 104 others who didn't report for work. The jail is being guarded by state police, and the conty is planning to hire replacements for the guards who were fired.

County Attorney Robert Sotrum said last night, "When the jail guards walked out, they engaged in an illegal action which put the citizens of the county in substantial danger. This issue is not discussable."

The final issue separating the two sides is the union's demand for permission to charge strikers' time off the job this week to paid annual leave.

When they emerged from last night's meeting at the Federal Mediation and Conciliation Service in Washington, county officials and union leaders said they were willing to return to the bargaining table whenever Flores called a new session.

AFSCME representative Paul Manner said yesterday that if the 18-month contract dispute was not resolved this weekend, his uion would continue to strike next week.

Before yesterday, Hogan had refused to allow the county to reopen negotiations while any union members remained on the picket lines outside county facilities.

He apparently backed off that pledge at the urging this week of the county Circuit Court judge who has been hearing arguments in the prolonged labor dispute.

Meanwhile, picket lines remained around county facilities with county officials claiming only 678 workers were off the job today. The union maintained that 80 to 90 percent of its 1,500 members have participated in the strike.

Jail officials yesterday began interviewing former D.C. corrections guards who were laid off in the city's budget crunch. Spokesman James O'Neill said the county corrections department also expects to hire guards from a private security firm by next week to help man the jail.

O'Neill said the department expects to fill 99 jail guard positions on a temporary basis with former District guards and security agency employes. Jail security now is being maintained by the Maryland State Police.

Several county facilities, including the landfill and other public works operations, remained seriously curtailed.

The county animal shelter, which has been closed for the last few days because of the strike, reopened yesterday with staff from other county departments, volunteers and former employes, according to department officials. d