United States will impose visa bans on foreign nationals it deems to be censoring Americans, the Secretary of State, Marco Rubio, said yesterday, suggesting the new policy could target officials regulating U.S. tech companies.

Rubio did not name specific instances of censorship, but U.S. tech companies and the Trump administration have challenged U.S. allies in Europe, alleging censorship of social media platforms, but restricting officials from visiting the U.S. appeared to be an escalation by Washington.

Rubio said in a statement that a new visa restriction policy would apply to foreign nationals responsible for censorship of protected expression in the U.S. He said it was unacceptable for foreign officials to issue or threaten arrest warrants for social media posts made on U.S. soil.

“It is similarly unacceptable for foreign officials to demand that American tech platforms adopt global content moderation policies or engage in censorship activity that reaches beyond their authority and into the United States.

“Free speech is among the most cherished rights we enjoy as Americans. This right, legally enshrined in our constitution, has set us apart as a beacon of freedom around the world.”

U.S. social media companies, like Facebook and Instagram, have said an EU content moderation law, the Digital Services Act, amounts to censorship of their platforms.