The Department of Education opened a civil rights investigation Monday into states that are blocking school mask requirements.

The department wrote a letter to top officials in Iowa, Oklahoma, South Carolina, Tennessee and Utah that a direct investigation has been opened to determine whether the five states’ blocking of COVID-19 safety protocols is “preventing school districts in the state from considering or meeting the needs of students with disabilities.”

"The department has heard from parents from across the country – particularly parents of students with disabilities and with underlying medical conditions – about how state bans on universal indoor masking are putting their children at risk and preventing them from accessing in-person learning equally," said Education Secretary Miguel Cardona.

"It's simply unacceptable that state leaders are putting politics over the health and education of the students they took an oath to serve. The department will fight to protect every student's right to access in-person learning safely and the rights of local educators to put in place policies that allow all students to return to the classroom full-time in-person safely this fall."

State governors had received a letter from Cardona last week warning that their ban on mask mandates are putting students at risk and “may infringe upon a school district’s authority to adopt policies to protect students and educators as they develop their safe return to in-person instruction plans required by federal law.”

In the letter, Cardona said the Office of Civil Rights would prepare to investigate any claims that come forward to “ensure that all students have access to this fundamental right of education” as part of President Joe Biden's written memo ordering Cardona to use all legal means possible to ensure safe in-person education to the nation's children.

This warning letter included all states that are under investigation, as well as Arizona, Arkansas, Florida and Texas. The Education Department said that the four states are not under investigation since their bans are not being enforced.

In response to the investigation, Iowa Gov. Kim Reynolds posted comments on Twitter.

"Iowa was able to reopen schools safely and responsibly over a year ago. President Biden and his team know this, yet they’ve decided to pick a political fight with a handful of governors to distract from his own failures - Afghanistan, the border, inflation, and more," she posted.

"As I’ve said all along, I believe and trust in Iowans to make the best health decisions for themselves and their families.

"Iowa’s democratically elected legislature endorsed that view as well when they passed a law to support a parent’s right to decide what’s best for their own children. In Iowa, we will continue to support individual liberty over government mandates."