Prince George's County officials notified members of the current police recruit class yesterday that there is a "substantial probability" that they will lose their jobs after July.

In a letter sent to the 48 members of the police recruit class, which is scheduled to graduate in April, Michael J. Knapp, the county personnel officer, said that the layoffs will be necessary unless the county makes major cuts in other areas of the police budget.

County officials have said that layoffs, pay cuts and new taxes are necessary to offset a $72.3 million revenue shortfall that they blame on a severe downturn in the regional economy. The county already has laid off 190 employees, but none were uniformed officers.

County officials have told representatives of the police union, Fraternal Order of Police Lodge 89, that unless officers forgo a scheduled 7 percent pay raise and other merit raises, the county will dismiss 160 to 230 officers.

"You can't have 10 percent pay raises and no firings and still end up with a $70 million cut," said County Executive Parris N. Glendening. "We're asking all employees across the board to make sacrifices."

A layoff of the magnitude proposed would eliminate the staffing gains that the county has made during the last year and reduce the strength of the department to levels below that in the spring of 1989, when a large and costly recruiting program began.

Glendening, acting under a County Council mandate, had pledged to increase the police force from about 1,050 officers to 1,400 officers after it was reported in 1989 that staffing shortages were so severe that often as few as 51 officers at a time were patroling the county.

FOP President Darryl A. Jones Sr. said yesterday that union members do not want to accept a pay cut. The police department, Jones said, already has taken a personnel cut by losing a planned 175 new officers, in addition to the proposed layoffs.

"We've already lost people that we needed desperately and had been promised," Jones said. "It really annoys me that public safety is being asked to make another sacrifice."

Police Chief David B. Mitchell met with the recruits yesterday to tell them of the potential layoffs. It was "one of the most difficult tasks I have ever performed in my career as a police officer," Mitchell said.

One recruit wrote on the classroom blackboard, "Keep the Faith," which Mitchell, obviously moved, initialed. The recruits declined to comment yesterday, but when leaving the academy, blew their automobile horns in a gesture of protest.

Mitchell said the department will work to minimize the number and impact of the layoffs. However, he said that any layoffs "absolutely" will set back plans to implement community-oriented police programs and reach affirmative action goals.

As recently as August, two weeks before the primary election, Glendening said that he still planned to bring the size of the force to 1,400 officers. The department currently has about 1,230 officers.

Shortly after that, Glendening canceled plans to hire 200 officers.

The current recruits were hired in October, about the time that county officials said revenue projections were falling short.

The County Council increased apartment licensing fees, raised the hotel-motel tax and increased the transfer tax last year specifically to provide revenue for new officers. Some council members said yesterday that they felt betrayed by the move to cut officers.

"The fact is that we have to cut expenses, but we never should have told the public that we were going to raise taxes so we could hire new police officers and then not do it," said council member Sue V. Mills. "The county collectively should have a red face."Staff writer Lynne K. Varner contributed to this report.