Secretary of State Marco Rubio is warning hostile state actors, Iran in particular, that the United States will no longer engage in “hostage diplomacy.”

Rubio made the remarks ahead of a flag-raising ceremony at the State Department to mark U.S. Hostage and Wrongful Detainee Day. The top diplomat asked for a moment of reflection, noting the recent return of six U.S. soldiers killed in the Iranian counterstrikes following Operation Epic Fury.