The Philadelphia School Reform Commission adopted a $2.8 billion "interim" budget Tuesday night, formally endorsing deep cuts, but signaling that it hopes it can roll back the most painful ones.

"Many of the critical building blocks of the school district's budget are still uncertain," chief financial officer Michael Masch told the SRC at a dramatic special meeting.

But unless talks in City Hall and Harrisburg yield new funding, full-day kindergarten is gone, as is most transportation. There will be 3,409 fewer positions next year, including 1,158 fewer teachers, and cuts to early-childhood education, individual school budgets, nurses, counselors, the arts, and more.

And the SRC also warned that if its five unions did not come up with $75 million in concessions by June 30, Superintendent Arlene C. Ackerman would recommend that the commission vote to cancel their contracts - an unusual power given to the SRC by the state takeover law, but not used in a decade.

Jerry Jordan, president of the Philadelphia Federation of Teachers - the district's largest union - said he had not renegotiated and would not do so. He said the PFT negotiated a contract in good faith and already gave concessions.

"The School Reform Commission and the superintendent have really lost their credibility with their actions tonight," Jordan said in an interview. "This gap wasn't created by us, and now they're asking us to bear the burden."

Asked if he believed the district was prepared to cancel the teachers' contract, Jordan said the union would "deal with that when we have to."

Jordan also objected to a resolution passed Monday night that would exempt teachers at Promise Academies - district-run turnaround schools - from layoffs. He has vowed to fight that measure in court.

The budget passed 3-1. Commissioner Joseph Dworetzky said he supported the budget only "reluctantly."

Commissioner Johnny Irizarry, who asked several questions about cuts to alternative-school providers, voted no.

"I just felt there were too many unanswered questions," Irizarry said after the meeting. "I didn't agree with some of the cuts."

Legally, the district must adopt a spending plan by the last day of May, but Masch said he fully expected to ask the SRC to adopt an amended budget - restoring some cut funding - over the summer.

The SRC got an earful from dozens of speakers at the three-hour meeting.

City Councilman Bill Green, a frequent district critic, said he hoped to help restore some funding, but upbraided district officials for their approach to cuts.

"Stop the fearmongering, adopt a responsible budget, and treat your partners at the city and state like adults," Green said. "Restore things that are proven, like full-day kindergarten and early-childhood education, then come make the case for things that aren't yet proven."

Parent Rebecca Poyourow said she was "concerned - to put it mildly - with what seems like a fundamental lack of oversight and appropriate policy-setting on the part of the SRC and the Philadelphia School District when it comes to stewardship of the funds the district does receive."

Green, Poyourow, and others suggested the district's priorities were out of order - funding an 18-day summer school at a price tag of about $23 million, but cutting transportation and full-day kindergarten, for instance, and paying big salaries to central administrators, but cutting jobs and counting on givebacks from teachers.

Poyourow, whose older son is a first grader at Cook-Wissahickon Elementary in Roxborough, is one of hundreds of parents who have mobilized to lobby legislators for more funding.

"Our message to the members of the SRC and to the district is that we believe in our schools, and we will fight for public education, but you have got to put this house in order," she said.