NASHVILLE (AP) — Some Democratic lawmakers say they support a proposal by Gov. Bill Haslam that would place stricter enrollment requirements on online public schools established in Tennessee.

The administration bill would cap student enrollment at a so-called virtual school at 5,000 students, and initial enrollment would be limited to 1,500, depending on the school's performance.

The measure would cap enrollment at Union County's rapidly growing online public school run by K12 Inc., the nation's largest publicly traded online education company, under contract with the Union County Public Schools system.

Last year, Education Commissioner Kevin Huffman called first-year test results at the Tennessee Virtual Academy "unacceptable."

State figures showed the academy fell into the bottom 11 percent of schools for student gains as measured under the state's value-added assessment system. The cyber school scored a 1 on the 5-point scale.

Since then, Academy head Josh Williams said the school has taken steps to improve student performance. He did not immediately respond when asked for comment about Haslam's proposal.

However, Williams and a K12 official were heavily criticized during a House Education Committee meeting on Tuesday by lawmakers dissatisfied with the school's performance.

"We have done a lot over the last 5 years in education reform in this state, and this is a setback, so I would admonish you to pay attention," said Rep. Joe Pitts, a Clarksville Democrat and committee member.

Democratic Rep. Brenda Gilmore of Nashville said later that she supports the Republican governor's measure because she believes virtual schools remain unproven.

"I think we have not had a lot of success with virtual schools, and we could use those dollars elsewhere," she said.

Rep. John Deberry said he believes there are some positives to virtual schools, "but there are still questions."

"So I think what the governor is doing is wise," said the Memphis Democrat.

Under a law passed in 2011 by the Republican-controlled General Assembly, the academy began operations in the 2011-2012 school year, enrolling 1,783 K-8 students from across the state. State payments to K12 are a little over $5,000 per pupil.

According to Haslam's proposal, if a school meets state guidelines for "student achievement growth" then it may exceed the initial enrollment limit.

Enrollment of students living outside the school district that establishes the virtual school can't be more than 25 percent of the district's enrollment.

However, the bill states that a virtual school in operation as of January 1, 2013 "may continue to serve the students enrolled in the school as of January 1, 2013."

Education Department spokeswoman Kelli Gauthier said the proposal is intended to "enhance the accountability for virtual schools, and to base their future growth on demonstrated performance."

"This is a matter of learning from the first year of implementation of the Virtual Schools Act and making improvements with a focus on student achievement," she said in an email.

Rep. Mike Stewart said he supports Haslam's proposal to a degree, but ultimately believes virtual schools are a drain on taxpayer dollars and should simply be done away with — and he's proposing legislation to do just that.

"I think he should ban virtual schools altogether," said the Nashville Democrat.