Sen. Ted Cruz (R-TX) expressed concern Tuesday that “deep-state forces” are behind President Trump’s dismissal of former national security adviser John Bolton. “I sincerely hope his leaving the White House does not mean that the deep-state forces at State and Treasury—who have been fighting tooth and nail to preserve the Obama Iran nuclear deal—have finally convinced the president to go soft on Iran,” Cruz wrote in a series of tweets. “Relaxing the maximum pressure strategy, which is succeeding in dramatically weakening the world’s leading state sponsor of terror, would be an enormous mistake.” He additionally warned that the Trump administration could backtrack on their “single greatest national security victory” and “return to Obama’s failed foreign policy” if Europe is allowed to send an “economic lifeline to the Ayatollah.”

In a Tuesday tweet, Trump confirmed that he had “disagreed strongly” with Bolton about a number of foreign policy issues—namely Iran, Afghanistan, and North Korea. The president said that he dismissed Bolton, while Bolton insisted that he resigned from his post.