NASHVILLE (AP) — Gov. Bill Haslam's office is dismissing as a "political stunt" a letter signed by 15 Republican lawmakers demanding the resignation of Education Commissioner Kevin Huffman.

The letter dated Thursday cites complaints from school administrators, teachers and students about Huffman's leadership style as his department implements a series of changes in K-12 education.

"Commissioner Huffman has overstepped his authority and failed to serve in the best interest of the citizens of this state," the letter said. "Anything short of his immediate removal will be unacceptable."

The lawmakers signing the letter are strongly identified with the tea party wing of the party — including Rep. Joe Carr of Murfreesboro, who is challenging incumbent Lamar Alexander for the Republican nomination for the U.S. Senate in August.

Many of the signatories were involved in a legislative effort earlier this year to thwart Haslam's wishes by delaying the implementation of Common Core standards and related testing requirements.

Haslam spokesman David Smith said the Republican governor was standing by Huffman.

"The governor believes there is a more productive way to discuss something so significant than through a letter by a small group of legislators more interested in trying to get headlines than substance," Smith said.

"It is disappointing they chose a political stunt instead of constructive dialogue," he said.

The letter follows a petition signed by nearly half of the state's superintends last year criticizing Huffman's leadership of the department, arguing that the commissioner had "no interest in a dialogue" with local school leaders and that efforts to improve schools were being thwarted by by low teacher morale because of policy changes on the state level.

Huffman joined Haslam's cabinet in 2011. He was previously vice president of public affairs at Teach for America, a program that has tried to improve classroom teaching by placing recent college graduates in low-income schools and is often criticized by teacher unions.

The State Collaborative on Reforming Education, which has advocated for Common Core and other education initiatives championed by the Haslam administration, said Huffman has played a key role in improving standards in the state.

"We are raising expectations in our classrooms, better supporting our educators, and prioritizing college and career readiness," spokeswoman Teresa Wasson said in an email.

"We encourage state leaders to put aside individual differences and political rhetoric and work together in ensuring that Tennessee students remain at the center of this work," she said.