President Mahmoud Ahmadinejad fired his intelligence minister Sunday after being forced to remove his first vice president, a close adviser.
The Shiite militant organization in Lebanon draws money and ideological guidance from Iran's supreme leader.
The role of the supreme leader has changed, but Iran's top cleric, Ayatollah Khamenei, still holds sway. How the political system in Tehran works, and who will determine what comes next.
Hopes dimmed for a thaw in US-Iran relations as the Iranian president criticized his American counterpart Barack Obama for echoing Bush rhetoric.
Protesters reported beatings and shootings near the parliament Wednesday. Regime opponents vowed to persist with protests that have deepened a cultural divide between hard-liners and more moderate reformers.
The president responded to critics who accused him of not condemning Iran's crackdown of pro-democracy protesters. But he also kept his options open.
The president's ties to military and security forces, as well as his hardline foreign policy, are among the factors cited for his support from the country's supreme leader.
The Revolutionary Guard vowed to stop the street demonstrations, causing some protesters to stay home. But others gathered Monday to honor the death of Neda Soltan.