SPRINGFIELD, Ill. — Public schools across Illinois are feeling the pressure of a state financial backlog, and public university officials are near rebellion about their own IOUs from the state.

The presidents and chancellors of 12 public university campuses sent a letter to Gov. Pat Quinn and Comptroller Dan Hynes asking them to set a payment schedule so they can collect more than $735 million in state payments owed them.

Closer to home, Alton’s Community Unit School District No. 11 is waiting on more than $4 million from the state, and administrators say the backlog is forcing them to consider layoffs. Edwardsville’s School District 7 and Collinsville’s Community Unit School District No. 10 are also short about $4 million each. Belleville Township 201 High School District is owed more than $2 million.

“I’ve been a superintendent for 16 years altogether, and this is the worst state of finance in education I’ve ever seen,” Alton superintendent David Elson said.

The overdue payments are a result of a growing state deficit that likely will reach $13 billion this year. The state is limping through the fiscal year by borrowing money and leaving bills unpaid, including a backlog of unpaid state appropriations.

The university officials said lawmakers approved a general revenue budget for the fiscal year that gave universities nearly $1.4 billion to pay for things such as salaries, libraries, utilities, maintenance, equipment and supplies. They say they have billed the state for nearly $1.1 billion of that but have collected only $335 million.

Hynes’ office, which issues the checks to pay the state’s bills, said the backlog of unpaid bills totals $3.6 billion. He blamed lower-than-expected revenue and said the state spends more money than it brings in.

The worst part, school and university officials say, is that no one is sure when the money is coming — or if it will even arrive this year.

Though the state has kept up with general payments to local schools twice a month thanks to federal stimulus money, grants for special education programs and student transportation went largely unpaid until the beginning of January, and schools are still waiting for millions in those categories.

Carol Knowles, spokeswoman for the comptroller, said the office ordinarily pays bills as they come in, but the state’s billion-dollar backlog has forced a more “compassionate” and selective approach, putting education and essential social services first.

Even with those small payments, school district officials say layoffs or furloughs and program cuts are becoming a serious possibility as Illinois’ billing backlog grows.

Uta Robinson, director of business affairs for Collinsville’s school district, said the district will have to borrow internally from other funds and borrow against future tax payments to stay afloat.

Administrators in Alton will need to trim about $3 million from their budget for next year, even if the state keeps up with regular payments for general school funding, Elson said.

But that’s a large assumption, considering lawmakers only were able to cover those payments with about $1 billion in federal stimulus money.

Bill Phillips, associate professor at the University of Illinois-Springfield and former superintendent of Belle Valley School District in Belleville, said school districts have to establish their work force for the next year at least two months before the current school year ends, under state law.

Administrators will have to make predictions about how many employees they can afford to keep before then.

“It’s easy to say we’re going to cut the fat in government,” Phillips said. “But in terms of school districts, you’re going to lay people off, you’re not going to have programs or you’ll have more kids in a class because you have fewer teachers.”

The state’s public universities have cut budgets, imposed furlough days, and frozen hiring and salaries to conserve cash.

The University of Illinois has a backlog of state appropriations totaling about $431 million, said interim president Stanley Ikenberry.

U of I employees have taken 4 percent pay cuts this year, and Ikenberry has said tuition will likely be raised at least 9 percent this summer to help the school get by.

“At some point we will be unable to meet payroll and complete the academic year unless there are significant payments from the state as promised. My hope is that the governor, leaders and members of the General Assembly will come together immediately to address the state’s escalating financial crisis,” Ikenberry wrote in an e-mail to faculty and staff.

Ikenberry said an income tax increase was the most obvious remedy for the state’s financial problems, but even that won’t be enough.

“The hole that Illinois has managed to dig for itself is so deep that it’s not going to be able to cut its way or tax its way out of the hole,” Ikenberry said. “It’s going to take a combination of both.”

Quinn, a Democrat, has proposed raising the income tax rate, but lawmakers were reluctant to support that before the Feb. 2 primary. He has predicted they will pass a hike later this year.

The two Republicans locked in a tight race to face off against Quinn have vowed to fight any effort to raise the income tax before the November election.

A slim margin of votes separated state Sens. Bill Brady of Bloomington and Kirk Dillard of Hinsdale after last Tuesday’s primary, and neither will declare victory or concede until all absentee and outstanding ballots are counted.

The Associated Press contributed