MANKATO — The two large organizations representing Minnesota cities are warning of very difficult days — and years — ahead.

A report by the League of Minnesota Cities released Thursday said that no cities will escape the inevitable trend toward ever-steeper budget cuts.

“These findings are staggering — that cities of all kinds will fall into a deficit within the next five years and be unable to provide the level of services residents and businesses have come to accept,” the report states. “In other words, it won’t matter where a city is, how big or small its population, what its tax base composition is, what its local economy looks like ... all types of cities will be in the red if nothing changes.”

The report, done in conjunction with the University of Minnesota’s Humphrey Institute of Public Affairs, projects city spending will rise 5.5 percent each year simply by maintaining existing services. The increases will be driven by inflation, rising health care costs and demographic changes in the population.

Revenue increases, because of declining state aid and a reluctance to increase property taxes, are estimated to rise 3.7 percent annually.

That means deficits by 2015 for all types of cities. And because cities are required by law to have balanced budgets, major changes will be required, according to the report.

“To illustrate, in a deficit situation as severe as projected, cities as a group would have to eliminate a wide range of services or double property-tax levies.”

To fill those deficits with spending reductions would mean the loss of services not deemed vital. Examples of what is likely to be lost, according to interviews with city officials, are senior citizen centers, libraries, municipal swimming pools, ball fields and hockey rinks, and after-school programs.

City infrastructure such as sidewalks and streets could also crumble as maintenance schedules aren’t met.

“This isn’t hyperbole — it’s simply the continuation of the slow path of degradation Minnesotans have been seeing for the past seven years,” the report states.

Mankato City Manager Pat Hentges, speaking from the League meeting in St. Cloud where the report was released, said he was struck by how demographic changes will influence city budgets in the next 15 years. An aging population, combined with a growing number of people below the poverty line, will boost demand for services even as income levels decline for much of the population.

And while all cities in the state will feel the impact and will face deficits, Hentges also noted the news was substantially worse for some types of cities.

Central cities — namely Minneapolis and St. Paul — are facing the steepest deficits as a percent of their total revenue. Older suburbs without room to grow, towns of under 1,000 population, and greater Minnesota regional centers (Mankato’s category) face the next most difficult future. Outer suburbs, growing cities on the fringe of the metro, and outstate towns larger than 2,500 are facing less severe deficits.

The report calls for a variety of meetings across the state to get ideas and input from “Minnesotans of all walks of life” to do a “complete rethinking of the services provided and how to pay for those services.”

A report earlier this week by the Coalition of Greater Minnesota Cities to the North Mankato City Council had a shorter-term focus but more bad news.

The next governor and Legislature are going to be facing a two-year budget deficit of $5 billion to $8 billion, Coalition lobbyist J.D. Burton told the council. The red ink threatens the future of Local Government Aid, a state funding source for less-property-rich cities that makes up a substantial but declining part of their budgets.

Burton urged the council to question candidates for governor and the Legislature about their commitment to protecting LGA from budget cuts. If the aid program is eliminated, North Mankato would have to raise its property-tax levy nearly 28 percent just to maintain current services, he said.

North Mankato Mayor Gary Zellmer said residents need to be made to understand that LGA comes from the state income and sales tax, transferring the revenue to cities to keep property taxes down. If the program disappears, property taxes will go up, but the income and sales tax rates won’t go down, Zellmer predicted.

“They’ll spend it on other things,” he said.

Hentges said city officials at the League conference remain resilient and haven’t given in to pessimism despite several difficult years and more on the horizon. But the session he’d left to do the phone interview was related to budget issues, and that was the topic of three of every four seminars offered at the meeting.

“It’s kind of a sign of the times,” he said.