Mayor Bill de Blasio needs another extension.

Four weeks into the school year, de Blasio said he wasn’t yet ready to detail his vision for improving with the city’s worst-performing schools, saying those plans would be released soon for the second time this month.

“We know that many parts of our school system are not working the way they should,” de Blasio said Monday. “We think there are things that we can do to support them, but we’ll have more to say on that in the next few weeks.”

The comments echo the mayor’s first-day-of-school promise of a “coherent, energetic, purposeful effort to save schools” that would “start to be felt literally in the coming weeks.” In the four weeks since, teachers and students have settled into a new year, but principals of struggling schools said that support has been slow to arrive.

Nearly 30 schools whose test scores and graduation rates put them among the state’s bottom 5 percent require improvement plans created by the school and city officials—plans originally due at the start of the school year that the city received a three-month extension to submit. And a number of education observers, from researchers to charter school advocates, have pointed to the delays in questioning the administration’s commitment to those low-performing schools.

On Monday, de Blasio didn’t dispute the notion that some of the city’s schools needed to improve. But he emphasized the citywide programs his administration has prioritized and already put in place, especially the rapid expansion of pre-kindergarten and after-school programs for middle school students. He also cited his plans to establish more schools that offer expanded social services and changes to the school day that resulted from a new teachers-union contract.

“We’re devoted to making every school work, and that is the structural change that’s needed in this city,” de Blasio said.

De Blasio’s comments come as the city’s education policies are under increased scrutiny. Families for Excellent Schools, an advocacy group that wants to see more charter schools in the city, will spend nearly $500,000 on television ads this week that put a spotlight on the more than 300 city schools where nine out of 10 students don’t earn a proficient score in reading or math. The organization is also behind a large rally on Thursday that promises to bring renewed attention to the city’s charter schools, which serve 8 percent of the city’s more than 1 million students.

De Blasio and his allies have responded with critiques of their own about Families for Excellent Schools and some of the city’s most prominent charter school networks.

Alliance for Quality Education, a union-supported advocacy group that pushes for more school funding, has sought to discredit Families for Excellent Schools’ campaign in recent days, saying its funders seek to undermine public education by diverting money away from traditional schools. On Monday, de Blasio said he agreed that outside political groups should disclose their funding.

“I think disclosure is the one thing that everyone should agree on,” de Blasio said. “So the public can judge what interests are at play.”

De Blasio also said his focus as mayor will be less on expanding the charter school sector than on improving the traditional public schools that the vast majority of students attend. “That’s our first obligation to get it right,” he said.

Under Bloomberg, city officials believed the fastest and most effective way to improve schools was by shuttering the lowest-performing and replacing them with new ones, many of which were charter schools. Since 2002, the number of charter schools has increased from 11 to 197.

That growth is on pace to continue in the next several years, with the Success Academy charter network alone applying to open 14 schools in the next two years. SUNY’s Board of Trustees, which authorizes charter schools, will meet to vote on the applications on Oct. 8.

But critics of Success Academy and its CEO, Eva Moskowitz, are hoping to convince SUNY to reject the applications. Earlier this year, local elected officials sent a letter asking to call off any further expansion of the charter school sector until tighter regulations. A group of parents from about half of the city’s 32 Community Education Councils have also joined the calls, compiling a position paper that outlines their gripes about the charter school sector, which includes issues around student enrollment and retention.

De Blasio noted that some of the work to improve struggling schools is already underway.

“You’re going to see a series of additional reforms,” de Blasio said. “Each one of these takes real time to construct properly, but I can guarantee you that when it comes to our effort with struggling schools … you’ll see the effects during this school year.”