The Prince George's County government, suffering a revenue shortfall from the economic downturn, will lay off at least 100 and as many as 400 employees and leave 600 positions vacant in an effort to make ends meet, county officials said yesterday.

In addition, the county's annual sale of bonds to finance public works projects will be "substantially less" than the usual $50 million to $60 million to save on interest payments, according to Robert Duncan, deputy chief administrative officer.

The layoffs, Duncan said, are most likely to happen in agencies affecting the environment, public works and human services. No police officers, firefighters, corrections officers or deputy sheriffs will be affected, he said.

County Executive Parris N. Glendening, reelected to a third term on Tuesday, previously had announced a hiring freeze and the layoff of 10 employees who handle building permits and inspections, the area affected most directly by the downturn in new construction.

"Of all the different controversies and hard decisions in the last eight years, this is really the hardest," said Glendening, who met with union leaders yesterday to brief them on the budget crisis.

"You know reductions mean people and families," Glendening said. "I'd rather have a big controversy in the community and face an audience of 200 hostile people than what I'm going through now."

Other local jurisdictions are grappling with similar problems. Maryland officials have projected a $322 million shortfall. Virginia is trying to whittle $1.4 billion from a two-year budget. Montgomery County officials have taken steps to offset a projected $68 million shortfall.

Prince George's projected fiscal woes have grown from an initial revenue shortfall of $36 million in its budget of nearly $1 billion to almost $50 million.

Glendening said cutbacks he will announce next week are intended to anticipate a continued downturn in the economy through the next fiscal year.

"They will be hard, early decisions to put us on a stable course for at least 18 months," Glendening said.

There are about 6,000 budgeted positions, including the 600 that are currently vacant, in the county government. Duncan said current thinking in the county administration calls for reducing the authorized level to between 5,000 and 5,300. Taking into account the vacancies, that could involving laying off up to 400 workers.

About two-thirds of county workers are represented by unions under recently enacted three-year contracts. Glendening said he told union leaders yesterday that there will be no wage freezes. "We will honor all contracts," he said.

Glendening said that measures he has already announced have saved $17 million. That leaves $32 million in savings that must be achieved from the layoffs and other measures such as energy conservation. Reducing the bond sale saves $1 million a year in debt service for each $10 million of bonds issued.