In an escalating battle with Republican governors, President Joe Biden on Wednesday ordered his Education secretary to explore possible legal action against states that have blocked school mask mandates and other public health measures meant to protect students against COVID-19.

In response, the Education Department raised the possibility of using its civil rights arm to fight policies in Florida, Texas, Iowa and other Republican-led states that have barred public schools from requiring masks in the classroom.

Biden directed Education Secretary Miguel Cardona to “assess all available tools” that can be used against states that fail to protect students amid surging coronavirus cases.

“Some state governments have adopted policies and laws that interfere with the ability of schools and districts to keep our children safe during in-person learning,” Biden said in an executive order, adding that some states “have gone so far as to try to block school officials” from adopting safety measures.

It amounts to the sharpest threat yet against states that so far have ignored admonishments from the White House during the surging pandemic. The move also injects the federal government into mounting culture wars that have turned schools into battlegrounds in a debate over masks.

In an announcement on its website, the Education Department said policies that ban mask mandates could amount to discrimination if they lead to unsafe conditions that prevent students from attending school. The agency can launch its own investigations into potential violations, and it also responds to civil rights complaints from parents and the public.

“The department has the authority to investigate any state educational agency whose policies or actions may infringe on the rights of every student to access public education equally," Cardona said in a statement. He added that states banning mask mandates are “needlessly placing students, families and educators at risk.”

The agency’s Office for Civil Rights can issue a range of sanctions up to a total loss of federal education funding in cases of civil rights violations.

Florida Gov. Ron DeSantis has pressed ahead with a ban on school mask requirements, and the state’s education officials are now weighing whether to withhold salaries of some superintendents that have defied the order. Texas and at least six other states have instituted similar prohibitions.

The state policies run counter to guidance from the from the Centers for Disease Control and Prevention, which recommends universal mask wearing for students and teachers in the classroom. In its guidance, the CDC cited the spread of the highly contagious delta variant.

Biden indicated last week that he believes he does not personally have the authority to overturn the policies, but he pleaded with Republican governors to reconsider their prohibitions. If they won’t help, he urged them to “at least get out of the way.”

While most states allow school districts to determine their own mask policies, some have fallen on either side of the debate. Some including California, Louisiana and Virginia have moved to require masks in schools for most students this fall. In other states that have barred mandates, leaders say it should be up to families to decide.

Protesters who oppose mask mandates have taken to state and local school board meetings in recent weeks, in some cases derailing the meetings.

In letters to Florida and Texas last week, Cardona said their prohibitions may violate the American Rescue Plan, which provided $123 billion to the nation’s schools to help them return to the classroom. The policies prevent schools from developing safe reopening plans, a requirement of the legislation, he said.

Similar letters are also being sent to Arizona, Iowa, Oklahoma, South Carolina, Tennessee and Utah, Cardona said on Wednesday.

“Let me be clear,” he wrote, “this department will continue to use every tool in our toolbox to protect the health and safety of students and educators and to maximize in-person learning as the new school year begin.”