TEHRAN, Iran — The balance of power inside Iran grew more volatile yesterday when supporters and critics of President Ahmadinejad won roughly equal representation in parliament.

Hard-liners will dominate the new “Majlis,” but the House will probably be split down the middle over Mr. Ahmadinejad’s fitness to rule.

With 190 of the 290 seats declared, Mr Ahmadinejad’s supporters had taken 67. His conservative critics, who blame him for Iran’s economic troubles, won 46. His opponents among Iran’s liberal reformers — roughly 90% of whose candidates were prevented from running — took 30 seats.

Ayatollah Ali Khamenei, the supreme leader, hailed the result as a “blow” against the “craft and cunning” of Iran’s “enemies.” He will maximize his own authority by arbitrating between the hardline factions.

Despite Mr. Ahmadinejad’s high profile, all vital decisions in foreign and domestic policy are taken by the supreme leader. From his office in Tehran, Mr. Khamenei presides over a web of control, which amounts to a state within a state. In theory, Iran’s government departments are run by ministers chosen by the president. In practice, the supreme leader has representatives in each ministry who answer directly to him.