In the latest controversy of the city’s most competitive mayoral race in a decade, a television ad recently released by Mayor John DeStefano Jr.’s reelection campaign triggered allegations of unethical campaign tactics from his opponents Thursday.

Superintendent of New Haven Public Schools Reginald Mayo asked staff members to appear in the ad, a 30-second spot in which several students, a teacher and a principal praise DeStefano’s school reform efforts. While it does not run afoul of state election law, his opponents accused the mayor of using his power for political gain, a claim vigorously denied by the DeStefano campaign.

Jeffrey Kerekes, who has emerged as the mayor’s fiercest critic, called on DeStefano to take the ad off the air immediately.

“This all shows that [DeStefano] has to, in effect, cheat his way back into office by recruiting schoolchildren to participate in campaign videos instead of natural supporters,” he said. In the ad, titled “On the Job and On Our Side,” Davis Street School pre-K teacher Danielle Zito, Davis Street principal Lola Nathan, and several students aged from pre-K to high school praise DeStefano’s education record. The ad’s script boasts that the mayor’s tenure has coincided with an expansion of pre-K education, the establishment of the New Haven Promise college scholarship program, and improvements in standardized test scores.

Mayo, who became superintendent two years before DeStefano rose to power in 1993, recruited participants in the video by calling people he thought would be interested, Danny Kedem, DeStefano’s campaign manger, said Thursday. The recruiting was Mayo’s idea, not DeStefano’s, schools spokesman Chris Hoffman said, adding that Mayo did it in his capacity as a private citizen.

Still, Mayo’s use of his connections in the schools to help DeStefano win reelection smacks of unethical behavior and reinforces a perception of political entrenchment in the city, mayoral candidate Clifton Graves said.

“It’s not surprising — there’s a symbiotic relationship between the mayor and the superintendent — but it was unwise and inappropriate,” Graves said, adding, “We need to show that we’re not going to just let things slide in this community.”

But Kedem argued that there is nothing wrong with Mayo calling on acquaintances he has made during his two decades as schools chief to support the mayor’s reelection bid.

“It is natural for people who are closest to the schools and city government to want to support a candidate who demonstrates a clear vision in getting our kids into college and making the right investments for our families,” Kedem said in an email Thursday night. “The people who volunteered to be in our commercial were happy to do so. Other interpretations are just sour grapes.”

State law forbids municipal employees from soliciting “a contribution on behalf of a candidate for municipal office” from people under their supervision, but since the participants in the ad were unpaid volunteers, their appearances do not meet the definition of “contribution.”

The ad, which was filmed Aug. 16 at Mauro-Sheridan School, will air mostly on channel 8 and on some cable channels, Kedem said.