President Biden ordered Education Secretary Miguel Cardona on Wednesday to take action against governors who have banned universal masking in public schools, taking a tough stand against those who he said are trying to “block and intimidate” local schools officials.

At a news conference, Biden said his administration would not “stand by” and allow governors to prevent local districts from “keeping students safe” with masking mandates for the new academic year as cases from the delta variant of the coronavirus are skyrocketing.

He did not name any specific governor, but Republican governors Ron DeSantis of Florida, Greg Abbott of Texas and Doug Ducey of Arizona, are among those state leaders who have threatened to withhold funding from districts or take other action against those districts that defy them. In Florida, Miami-Dade County Public Schools, the fourth largest district in the country, on Wednesday passed a universal masking mandate — with only a medical opt-out — as did Hillsborough County Public Schools.

“I’m directing the secretary of education to take additional steps to protect our children,” Biden said. “This includes using all of his oversight authorities and legal action if appropriate against governors who are trying to block and intimidate local schools officials and educators.”

The Centers for Disease Control and Prevention has said masking is one of the strongest tools that can be taken to protect the spread of the delta variant, which has caused a rise in pediatric coronavirus cases. The agency this summer, in a shift in guidance, recommended everyone over the age of 2 — even those who are vaccinated — wear masks inside school buildings.

But a handful of Republican governors and legislatures have banned mask mandates in schools.

In letters to the governors of Arizona, Florida, Iowa, Oklahoma, South Carolina, Tennessee, Texas, and Utah, Cardona said bans on school masking 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.”

Cardona, in a Wednesday post on the department’s Homeroom Blog, said the department can investigate any state educational agency whose policies or actions “may infringe on the rights of every student to access public education equally.”

“The department will also receive and respond as appropriate to complaints from the public, including parents, guardians, and others about students who may experience discrimination as a result of states not allowing local school districts to reduce virus transmission risk through masking requirements and other mitigation measures,” he wrote. “As always, the Department’s Office for Civil Rights evaluates allegations of discrimination on a case-by-case basis, looking at the specific facts of each case.

“In addition, the Department’s Office of Special Education Programs monitors states’ implementation of the federal special education law that requires that students with disabilities receive a free, appropriate public education,” Cardona said.

The New York Times first reported the education department’s new charge from the president.

The announcement came as some Republican governors are now trying to fight districts that are defying them on mask rules.

In Arizona, Ducey said the state would not direct federal coronavirus relief funds to any public school district that institutes a mask mandate — a move that could come under investigation from the Education Department.

In Florida, DeSantis has threatened to cut state funding to districts, as well as the salaries of superintendents and other education officials who defy his executive order stating that parents should be allowed to decide if their children wear masks in schools. Cardona has said school systems could use stimulus money to make up any lost funds.

On Tuesday, the DeSantis-controlled Florida Board of Education determined that the school districts in Broward and Alachua Counties had violated state law for imposing mask mandates with only medical opt-outs for families and it voted to consider sanctions. Board Chairman Tom Grady listed potential sanctions against defiant districts, including having the state remove school officials from their posts or act to oust local school board members.

The increasingly bitter battle over masking comes as Florida’s coronavirus case numbers are rising, with the seven-day average for new cases reaching a high of 24,720 on Tuesday. The number of cases in young people is rising as well, and the state’s Department of Health has restarted a case dashboard on its website. Thousands of students in school districts that have already started the 2021-22 school year are already in quarantine after being in contact with someone diagnosed with the contagious delta variant.

This wouldn’t be the first time the state considers acting against local school leaders. In 2019, DeSantis threatened to remove members of the Broward County school board after it supported then-Superintendent Robert Runcie, who the governor wanted to fire after the 2018 killings of 17 people by a gunman at Marjory Stoneman Douglas High School in Parkland. He acknowledged he lacked the authority to fire Runcie and did not move against board members then.

Biden promised Wednesday to stand with school districts that defied masking bans, saying, “This isn’t about politics. It is about keeping our children safe. It’s about taking on the virus together, united.”

He said he had phoned superintendents in Florida and Arizona to thank them for “doing the right thing and requiring masks in schools.”