Mayor Rahm Emanuel is planning to hire “hundreds” of additional police officers to stop the never-ending cycle of gang violence blamed for Chicago’s deadliest month in 20 years, the mayor’s City Council floor leader said Thursday.

Ald. Pat O’Connor (40th) said the wave of police hirings tied to the mayor’s 2017 budget is aimed at confronting a severe manpower shortage in the Chicago Police Department that can no longer be addressed with runaway overtime.

The Chicago Sun-Times reported earlier this year that the Police Department spent a record $116.1 million on overtime in 2015 — up 17.2 percent from the previous year — to mask a manpower shortage that has mushroomed under Emanuel with police retirements outpacing hiring by 975 officers.

“It’s less of a change in strategy and more of a response to this incredible streak of gun violence. By doing this, we hope to begin to get control of the gun violence that seems to grow all the time,” O’Connor told the Chicago Sun-Times.

“We have a large number of police officers retiring and a big increase in crime and people demanding more cops. We’re not gonna be able to keep up with attrition with the current numbers. We need to put more officers on the street.”

O’Connor refused to say how the hiring blitz would be paid for at a time when Chicago faces a $137.6 million budget shortfall, the city’s smallest in a decade.

But, he argued that there is room to maneuver, now that Emanuel has identified dedicated funding sources to put all four city employee pension funds on the road to financial health.

Last year, the City Council approved a $588 million property tax increase for police and fire pensions and school construction. Last week, Emanuel’s handpicked Board of Education signed off on a $250 million property tax increase for teacher pensions.

On Sept. 14, the City Council will be asked to put the final piece of the pension puzzle in place — by approving Emanuel’s plan to slap a 29.5 percent tax on water and sewer bills to save the Municipal Employees pension fund, the largest of the city’s four pension funds.

“If the aldermen have the courage to pass the water tax, there’ll be resources to do the things the aldermen and the mayor want to do” to hire more police officers, the mayor’s floor leader said.

Until now, O’Connor said, “Our ratings were going down. We didn’t have the luxury of hiring more police officers and adding to the pension and health-care problem. With overtime, you pay for it, and you’re done. Now, that we’re beginning to pull ourselves out of the hole, it’s loosening up a little bit. We can do things in a more traditional sense. We weren’t in a position to do that before.”

A top mayoral aide, who asked to remain anonymous,

said the tipping point for Emanuel was a summer surge in violence to levels the city hasn’t seen in decades.

Chicago closed the book on the month of August with 90 homicides. That’s the highest number of homicides in a single month since August 1996 and a 66 percent increase from the 54 murders during the same period a year ago, records show.

By early Thursday, Chicago had already recorded 469 homicides, putting the city on pace for 700 by year’s end. Chicago has not seen more than 600 homicides in a year since 2003 and not more than 700 homicides since 1998, records show.

“The dynamics have shifted over the summer. It tears at us,” the mayoral aide said.

“We’ve got to combat it aggressively, but combat it in the right way. You need more resources. There’s no question about that. It’s got to be a priority. We’re working day and night to figure that out.”

Emanuel campaigned for a first term on a promise to hire 1,000 additional police officers, then revised the pledge after taking office by adding 1,000 more “cops on the beat,” more than half of them by disbanding special units. The other half were primarily officers working desk jobs reassigned to street duty.

The mayor also balanced his first budget by closing police stations and eliminating more than 1,400 police vacancies.

The Chicago Police Department has roughly 12,200, sworn officers, including a class of recruits who completed their training at the police academy this week.

About 8,000 of those officers are assigned to the Patrol Division.

There are currently 468 sworn vacancies — not including the academy, according to Police Department spokesman Anthony Guglielmi.

When shootings and murders spiked and Chicago started making headlines as the nation’s murder capital, Emanuel used runaway overtime to tamp down the violence.

Emanuel and his Budget Director Alex Holt have argued repeatedly that overtime is a more flexible and cost-effective substitute for police hiring because the city doesn’t have to bear the cost of pensions and benefits for new officers.

Fraternal Order of Police President Dean Angelo has branded the mounting overtime unhealthy, unsustainable and a recipe for officer burnout.

He has urged his members to turn down all requests for “non-mandatory overtime” over Labor Day weekend to protest “continued disrespect of Chicago Police officers and the killing of officers across our country.”

Angelo has also warned that there are 291 officers age 55 with at least 20 years of service and “most of ‘em will be gone” by June, 2017.

The impending retirement wave is being driven, he said, by anti-police fervor sweeping the nation and by increased health care contributions tied to the new police contract that offer veteran police officers an additional nudge out the door.

For months, Emanuel has been walking a political tightrope.

He’s been trying to craft a new system of police accountability to restore public trust shattered by his handling of the Laquan McDonald shooting video.

And he’s been trying just as desperately to coax Chicago Police officers concerned about being caught on the next YouTube video out of a defensive crouch blamed for a precipitous drop in police activity.

“They’re human beings. …They’re conscious that there’s been a change. They’re conscious that they have now been somewhat demonized. But I would tell you, gangbangers are conscious. They’re the first ones to know that police have changed their behavior,” Emanuel said this week during an appearance on the WTTW-TV program, “Chicago Tonight.”

During that same interview, Emanuel said he was working with Police Supt. Eddie Johnson and Family and Support Services Commissioner Lisa Butler to devise a “comprehensive strategy to attack the issue of gun violence and gangs.”

The strategy will include “everything from the police, to children, to what we have to do for their safety, to guns, to making sure we’re providing hope where there is despair,’” the mayor said.

“It’s a complex set of problems that will be dealt with in a very comprehensive way,” Emanuel said, promising a major address on crime later this month.

The mayor’s decision to hire more police officers will be music to the ears of rookie Ald. Ray Lopez (15th), whose gang-ridden South Side includes Englewood and Back of the Yards.

In mid-July, the shooting of a 6-year-old Englewood girl caught in the crossfire between rival gangs prompted Lopez to demand that Emanuel finally make good on his 2011 campaign promise to hire 1,000 additional police officers.

“We have to decide if having our streets fully protected, if having our streets be places where children can come out without getting a bullet in their stomach just by sitting on the porch is worth paying for,” Lopez said.