Senate Judiciary ranking member Jeff Sessions (R-Ala.) charged Friday that the head of the U.S. Immigration and Customs Enforcement should not keep his job if he is unwilling to enforce Arizona’s new immigration law.

In an interview with the Chicago Tribune, Immigration and Customs chief John Morton said, “I don’t think the Arizona law, or laws like it, are the solution” and warned that his agency may not accept illegal immigrants arrested under the law. Arizona’s immigration measure, which goes into effect in July, would require immigrants to carry proof of citizenship and that law enforcement question anyone they suspect is in the country illegally.

Asked if he thought Morton should step down, Sessions told Fox News, “I feel like if he won’t enforce the law he shouldn’t have the job.”

“This is the chief law enforcement office, he should welcome the help he gets. He should not be publicly saying he does not want to cooperate,” Sessions said.

Sessions also attacked the Obama administration more broadly, arguing that Morton’s comments are part of a pattern and that it “looks like the administration is nullifying existing law … the only thing you can conclude is that they don’t want the legal system to work.”