The head of PBS said Friday that President Donald Trump’s executive order aiming to slash public subsidies to public broadcasting institutions PBS and NPR was blatantly unlawful. NPR’s chief also vowed to challenge the decision.

Public Broadcasting Service CEO Paula Kerger said the Republican president’s order “threatens our ability to serve the American public with educational programming, as we have for the past 50-plus years.”

“We are currently exploring all options to allow PBS to continue to serve our member stations and all Americans,” Kerger said.

Trump signed the order late Thursday, alleging “bias” in the broadcasters’ reporting.

The order instructs the Corporation for Public Broadcasting and other federal agencies to “cease Federal funding” for PBS and National Public Radio and further requires that they work to root out indirect sources of public financing for the news organizations. The White House, in a social media posting announcing the signing, said the outlets “receive millions from taxpayers to spread radical, woke propaganda disguised as ‘news.’”

The Corporation for Public Broadcasting, which funnels public funding to the two services, said that it is not a federal executive agency subject to Trump’s orders. The president earlier this week said he was firing three of the five remaining CPB board members — threatening its ability to do any work — and was immediately sued by the CPB to stop it.

The corporation distributes roughly a half billion dollars of congressionally-appropriated money to PBS, NPR and its local stations. In creating CPB, Congress forbade any federal agency or employee from direct control over educational television or broadcasting, said Patricia Harrison, its president and CEO.

NPR’s president and CEO also promised Friday to contest the decision as well. “We will vigorously defend our right to provide essential news, information and life-saving services to the American public,” Katherine Maher said. “We will challenge this executive order using all means available.”

The vast majority of public money for the services goes directly to its hundreds of local stations.