RIYADH, Saudi Arabia  The United States fears that Iran is drifting toward a military dictatorship, Secretary of State Hillary Rodham Clinton said Monday, with the Islamic Revolutionary Guards Corps seizing control of large swaths of Iran’s political, military and economic establishment.

Mrs. Clinton encouraged Iran’s religious and political leaders to rise up against the Revolutionary Guards, coming as close as any senior administration official has to inviting political upheaval in the country.

“That is how we see it,” Mrs. Clinton said at a televised town hall-style meeting of students at a university in Doha, Qatar. “We see that the government of Iran, the supreme leader, the president, the Parliament is being supplanted and that Iran is moving toward a military dictatorship.”

Her blunt comments carried particular resonance because of where they were delivered, in Qatar, a Persian Gulf emirate with close ties to Iran, and later in the day, in Saudi Arabia. But they built on the administration’s strategy of branding the Revolutionary Guards as an “entitled class” that is the principal culprit behind Iran’s nuclear proliferation and political repression.