Citing poor performance and low enrollment, education officials announced a proposal Monday to close six schools in New York City’s high-profile Renewal program and merge three others.

The proposal comes as the program, which involves spending hundreds of millions of dollars to flood low-performing schools with additional social services and academic resources, nears the end of its third year. Though Mayor Bill de Blasio has, unlike his predecessor Michael Bloomberg, been reluctant to close schools, he has also said that some might need to be shuttered as a “last resort.”

City officials called Monday’s proposal “aggressive” and schools Chancellor Carmen Fariña indicated the move is “what is best for students.”

“During this process we will work individually with every student and family to ensure they have a seat at a higher-performing school where they will receive the instruction and support they need to succeed,” Fariña said in a statement.

The Renewal program initially included 94 of the city’s most troubled schools, but due to previous mergers and closures that number had shrunk to 86. If the city’s proposal is approved by the Panel for Educational Policy — which is set to vote on it in March — 78 schools will remain in the program next year, according to the city’s press release.

That implies Renewal, which officials have explicitly called a three-year program, will continue into a fourth year. Education department spokeswoman Devora Kaye wrote in an email that the Renewal program will “continue to support schools that are improving,” but did not say how long the city anticipated the program would continue.

The plan includes closing six schools immediately, instead of phasing them out, starting next academic year: Two of them are junior high schools in the Bronx: J.H.S.145 Arturo Toscanini and J.H.S 162 Lola Rodriguez de Tio, a “persistently struggling” school the city had already proposed closing as part of a deal with the state.

Two high schools in the Bronx are slated for closure: Leadership Institute and Monroe Academy for Visual Arts and Design; as are two Brooklyn middle schools: M.S. 584 and the Essence School.

The city also plans to merge three schools: Frederick Douglass Academy IV Secondary School (to be merged with the Brooklyn Academy of Global Finance), Automotive High School in Brooklyn (with Frances Perkins Academy), and M.S. 289 Young Scholars Academy of the Bronx (with North Bronx School of Empowerment).

Automotive, according to the city’s proposal, will be the only merged school that will absorb the school with which it’s being merged, and stay in the Renewal program. But all of the merged schools would still get supports through the city’s community schools program.

Finally, the city’s plan includes truncating the middle school grades at two Brooklyn Renewal schools: P.S. 306 Ethan Allen and P.S. 165 Ida Posner.

The announcement comes three days after the New York Times first reported the closures and mergers.

In the case of the closures, according to the city, the Department of Education took into account performance and enrollment and included “a careful analysis of each school community.”

The six schools the city has identified for closure all have fewer students than when the Renewal program began in the 2014-15 school year. M.S. 584, for instance, has roughly 80 students this year, down from 224 six years ago.

Enrollment drops have plagued the vast majority of the city’s Renewal schools, which have collectively shed more than 6,000 students since the program launched.

In terms of performance, all six schools are clearly struggling. At the Essence School, for instance, 5 percent of its students were proficient in math or reading last school year — far below city averages.

But they are not necessarily the lowest-performing schools in the program, according to the city’s own benchmarks. The Essence School met one-third of the goals the city set for it last year — on measures including attendance and “rigorous instruction” — and even had one of its school climate goals converted into a “challenge target” because it was met before the deadline.

City figures show 26 Renewal schools met fewer benchmarks than Essence did last year. Asked why some lower-performing schools were not closed, the education department’s Kaye noted that a number of factors were considered beyond academic achievement and enrollment: feedback from families, staff turnover, history of interventions or improvement, and “research from schools in similar situations.”

“For each school we evaluated all these areas and have determined that closure would be the best course of action,” Kaye wrote.

Families for Excellent Schools, a pro-charter group that has consistently criticized the Renewal program, seized on the news of the closures and mergers as evidence of the program’s failure.

“Thousands of kids are still languishing in Renewal schools that are even worse than those now slated for closure,” CEO Jeremiah Kittredge wrote in a statement. The organization pointed to several schools in the program that have lower test scores and graduation rates than those the city plans to close.

But multiple observers said the city’s closure plans don’t necessarily mean the program isn’t working, especially since it explicitly targeted troubled schools.

“De Blasio had run on a campaign not to close schools, but that was destined to have mixed results on a school-by-school basis,” said David Bloomfield, an education professor at Brooklyn College and the CUNY Graduate Center. “You have dozens of schools [in the Renewal program] and a relative handful have been demonstrably unsuccessful. That’s not surprising.”

State Education Commissioner MaryEllen Elia also weighed in on the city’s proposal. “I’ve visited many of the city’s Renewal schools and have seen firsthand the hard work that’s taking place,” she said in a statement. “While many of these schools are showing important signs of progress, some continue to struggle — and those situations must be addressed appropriately.”

Megan Hester, an organizer at the Annenberg Institute for School Reform who has closely followed the program, wondered how the city might better serve the students who would potentially be displaced by the closures. City officials said they will launch a series of town hall meetings at each school starting next week, and offer individual support for parents to find new schools.

“I think for parents the question is, these schools weren’t able to be improved, so what’s the plan for the children in these neighborhoods?” Hester said. “What is the city learning from that and what are they going to do differently to make sure the next strategy works?”

Update 4:39 p.m.: This story has been updated to reflect additional responses from education department spokeswoman Devora Kaye.