Raising the ante in an already bitter feud, Mayor Mitch Landrieu’s administration issued a stop-work order Wednesday on the new $145 million Orleans Parish Prison, accusing Sheriff Marlin Gusman of “flagrant violations” of the city code and failing to build a lockup equipped to house all inmates, including those needing specialized medical and mental health treatment.

Construction on the 1,438-bed facility came to a halt about 1 p.m., infuriating Sheriff’s Office brass and opening a new front in an increasingly gloves-off legal battle over the ultimate size of New Orleans’ jail.

The stop-work order, accompanied by a related court filing and a tartly worded city news release, marked perhaps the sharpest escalation in the conflict to date. It drew swift recriminations from Gusman, who insists the new jail was built in keeping with city ordinance but is simply too small to house all inmates.

The Sheriff’s Office, after months of delays, had been planning to move inmates into the new jail as soon as August. But Wednesday’s developments threatened to delay its opening indefinitely as city officials and Gusman spar over whether the fourth floor of the facility can be renovated at this juncture.

The opening of the new jail has been seen as critical to the Sheriff’s Office ability to comply with a sweeping, federally monitored plan for reforms at OPP, where inmates for years have been exposed to violence and inhumane conditions.

“The city is standing in the way of the completion of our facilities, and it is using politics to confuse the public,” Gusman said in a defiant response. “On its face, the stop-work order is the city’s attempt to deceive the public into supporting its improper agenda. It is also an attempt to deflect the public’s attention from the real crime problem that the city is facing this year.”

The spat partly reflects differing views on how many inmates need to be locked up at any one time. Landrieu has been saying 1,438 beds should be enough to house all city prisoners, while Gusman says the mayor is being unrealistic and that hundreds more beds will be needed.

The Landrieu administration claims the matter already has been settled and accuses the sheriff of trying to “thwart the will” of the City Council.

Its lawyers have asked a Civil District Court judge to order Gusman to build the new jail as the city directed — and in particular, to honor the council’s requirement that the jail “accommodate any type of prisoner under any jurisdiction.” Alternatively, the city is seeking an injunction to prevent Gusman from completing the new jail in violation of city ordinance, City Attorney Sharonda Williams said.

Williams asserted in a court filing that the new jail “is appropriate only for housing general prison populations, requiring the sheriff to house other prisoners — female prisoners, juvenile offenders and prisoners with substance abuse issues — elsewhere.” The jail also does not contain a medical facility capable of serving all inmates, the city said. “Likewise, it does not contain adequate space for providing educational and job-training programming,” it added.

The concerns voiced by the Landrieu administration — which under state law must pay for the care of local inmates — are hardly new. City leaders for months have complained the jail was not being constructed in keeping with the city’s ordinance.

Jared Munster, director of the city’s Department of Safety and Permits, told reporters Wednesday that, until now, city officials “never had full notice that these (city code) violations were occurring,” in part because city inspectors had “very limited access” to the new jail. “This week, we decided that this has essentially gone on too long at this point, that we needed to take action,” Munster said.

Gusman, in his statement, countered that city inspectors have enjoyed “free access to the new construction, whenever they wanted to see it.”

“The city is well aware that this building is not in violation of the conditional use permit,” James Williams, an attorney for the sheriff, said in a telephone interview. “This issue should have been — and was — put to bed years ago. So for the city to make a maneuver like this was clearly designed to be a publicity stunt.”

The stop-work order reignites a debate over the feasibility of renovating the fourth floor of the new jail to accommodate so-called special populations of inmates. Landrieu’s administration has vigorously opposed a proposal by Gusman to construct another jail building — often referred to as a phase III facility — for upward of $80 million to house those inmates.

City officials filed a report in federal court Wednesday contending that “a modest renovation” of the new jail would equip it “to house the male and female inmates requiring specialized mental health and medical treatment.” The renovation would cost about $7 million and could be completed by Dec. 31, 2016, the report says.

Attorneys for Gusman, in their own court filings, contended that such a renovation is “no longer feasible” and “would result in large segments of the inmate population being housed in either temporary facilities or the long-crumbling jail facilities provided by the city.” They said the renovation also would “void the critically important warranties on the new building, and thus render the (Sheriff’s Office) responsible for any repairs which would have been covered by that warranty.

“The design team has also made it clear that due to the current building stage, any change order of such a magnitude could simply not be accomplished, and that the facility must be completed and rebid prior to such a drastic step.”

Gusman reiterated his desire to build a phase III facility with at least 380 additional beds, a structure he said would be dedicated to housing youthful offenders and inmates requiring mental health care. More beds could be added if the city fails to reduce its inmate population, he said.

“As crime skyrockets, the city continues to claim that the jail population will fall, and in this latest instance to numbers which have not been seen in this city in several decades,” Gusman’s attorneys wrote.

Landrieu’s administration has sought to prevent the construction of a phase III building at every turn.

“Our criminal justice system has incarcerated far too many people for a very long time,” said Charles West, director of the Mayor’s Office of Criminal Justice Coordination. “If we all work together as far as changing that, we definitely don’t need that phase III building.”

Follow Jim Mustian on Twitter, @JimMustian.