Mayor Sharon Pratt Dixon proceeded this week with plans to cut $13.5 million from the D.C. police department budget despite a warning from her police chief that the department could not absorb such a reduction without harming public safety.

Police officials said Police Chief Isaac Fulwood Jr. has stated privately that he could accept not hiring 200 additional officers, as Dixon proposed this week. But he and other officials have said they are much more concerned about Dixon's plan to allow the force to shrink by not filling positions vacated by officers who retire between now and the end of September.

Fulwood made the case against cutting the police budget in a memorandum to budget officials three weeks ago. "In order to carry out many of the planned initiatives to combat crime, drugs and violence, and to ensure that there is not a sharp dimunition in the level of community safety," he wrote, "full funding must be sustained."

Fulwood declined to comment yesterday on his memo, while Dixon administration aides sought to minimize any rift between the new mayor and the police chief, one of several holdovers from the administration of Marion Barry.

Administration officials said it was Fulwood himself who came up with the idea of scrapping plans to hire 200 officers, as a way of accommodating Dixon's demand to cut the police department's $257 million budget by 5 percent.

"There is every indication that the chief is on board and can live with conditions the way they are," said Vada Manager, Dixon's press secretary.

Dixon said Monday that the force could shrink by another 200 officers, and another administration source said yesterday the number could be 300 to 400 officers. The resulting force could number between 4,500 and 4,700 police officers, sources said. That would represent a sizable jump from the 4,070 officers on board in January 1990, but would be smaller than the target of 5,050 set by Congress last year.

But Fulwood's fear, sources said, is that the mayor's plan to shrink the force by attrition may result in larger-than-expected reductions. There is no way to predict how many officers will leave. A total of 980 officers are eligible for retirement as of today, and by the end of the year there will be 309 more.

"There's a lot of nervousness about all sorts of possibilities, about changes in compensation, no raises," a senior police official said. "People who can retire will retire, and all of a sudden you could go into a spin."

Dixon's decision to halt hiring in the department is one of the most controversial parts of her plan to cut spending this fiscal year by $136 million.

Other controversial features of the Dixon plan include proposals to trim Medicaid and welfare benefits, scale back funding for the summer youth jobs program, reduce the size of fire engine companies and eliminate the city's public law school.

At the District of Columbia Law School yesterday, Dean William L. Robinson told about 75 students and faculty members that he plans to appeal to the D.C. Council to overturn Dixon's proposal to phase out city funding for the school.

At least 10 council members signed letters to Robinson and to the American Bar Association saying the panel plans to continue funding the school "this year and in the future."

Meanwhile, Dixon aides said the mayor has asked 34 former Barry appointees to resign by March 8, including Social Services Commissioner Barbara Burke-Tatum; the chief of the city's drug treatment agency, John Jackson; and two deputy directors at the Department of Human Services.

All were asked by Dixon to stay on for 60 days to help with the transition.

Some will be permitted to obtain lower-ranking jobs in D.C. government.

Several key decisions announced this week by Dixon -- including those on the law school and fire department -- fulfill recommendations by the recent budget commission headed by Alice M. Rivlin.

In fact, Rivlin's commission recommended even more severe cuts in the police department, saying the city could eliminate at least 1,600 officer positions without affecting public safety.

The panel said the city has many more officers than comparably sized jurisdictions and could transfer many officers in desk jobs to patrol work.

Fulwood has criticized the recommendations, saying they are unrealistic and betray a lack of understanding about the department. But Dixon aides said the mayor gave significant credence to the Rivlin report, in part on the theory that the panel could not be entirely wrong about the need to cut the department.

"The commission said we can get by with a lot less police," said a city official who has participated in budget discussions. "Getting by with 300 or 400 or 500 less officers shouldn't be a major issue . . . . This is not the end of the world."

Another potential roadblock for Dixon is Congress. Last year it appropriated $23 million for the city to hire 700 new police officers, and several congressional sources and police union officials said yesterday that Dixon's plan, in effect, to use some of that money for other purposes violates the intent of Congress.

Dixon aides said the mayor plans to try to persuade Congress to alter the relevant statutes so the city can halt police hiring.

Also, Del. Eleanor Holmes Norton (D-D.C.) and Rep. Julian C. Dixon (D-Calif.), chairman of the House Appropriations subcommittee on the District, said they believed Congress would not insist that all the money be spent on police hiring.

With a $300 million budget deficit, Julian Dixon said, the mayor "has got to bite the bullet on even popular programs."

Staff writers Nell Henderson and Keith Harriston contributed to this report.