Los Angeles city officials moved ahead Wednesday with plans for laying off up to 278 employees, despite a last-ditch effort by union leaders to persuade Mayor Antonio Villaraigosa and City Council members to change course.

The city's employee negotiating committee, which is made up of the mayor and four council members, emerged from a closed-door meeting to announce that pink slips would go out as planned for the new fiscal year budget that starts July 1.

Budget officials had argued that job cuts could be avoided if employee unions agreed to some form of concessions, such as wage cuts or increased contributions to healthcare.

"The leadership of the city and the unions were unable to reach an agreement which was acceptable," said Matt Szabo, Villaraigosa's deputy chief of staff.

As many as one-third of the employees expected to lose their jobs are in the Department of Recreation and Parks, most of them child care workers.

Another third are in the city's libraries, while a much smaller number are in departments that handle services such as animal services, cultural affairs, information technology and transportation, according to personnel officials.

Those who receive notices are slated to lose their jobs July 1. "There's always the possibility that something could be done in the interim to avoid those layoffs," Szabo added. "But at this time, it appears very unlikely."

Another round of layoffs - possibly 245 - is expected in the next few weeks, city officials said.

Officials with the Coalition of L.A. City Unions had argued that the layoffs made no sense, since their contract states that any layoff would trigger a series of pay increases for those who are left behind. Budget officials put that cost at $29 million for the coming year and $98 million over three years.

"We've made very clear that the workers of the city are prepared not to take pay raises in order to save these...jobs," said Victor Gordo, an attorney with the coalition.

The negotiating committee met a few hours after Villaraigosa's appointees on the Board of Library Commissioners voted to seek a library tax measure for the Nov. 2 ballot. If placed on the ballot by the council, the measure would charge each property owner $39 per year - enough to restore 124 positions.

The measure, which would require a two-thirds vote for approval, would generate enough money to restore one day of library service per week at the city's 73 libraries. One day of service was eliminated because of the pending layoffs.

The council has already reduced the city's payroll by allowing 2,400 city workers to retire up to five years early with full pension benefits. And it has moved 408 workers into city departments that are not affected by the financial crisis.

Ninety employees were laid off earlier this year, according to personnel officials. Those workers were either represented by the Architects and Engineers Assn. or had no union at all.