President Vladimir Putin reversed himself Friday and authorized a parliamentary investigation into last week's terror attack on a school in southern Russia, the first time he has agreed to a public probe of this kind during nearly five years in power.

The Kremlin effectively controls Russia's parliament, and Putin assigned the task to the Federation Council, the especially compliant upper chamber. Critics said they doubted it would produce a genuinely independent inquiry into the violence in the town of Beslan, where at least 328 children and adults were killed.

But the decision to allow the inquiry represented a rare concession to public pressure by Putin, who refused to authorize probes after the sinking of the Kursk nuclear submarine in 2000 or the seizure of a Moscow theater in 2002. As recently as Monday, Putin had scoffed at the idea of a parliamentary inquiry as nothing more than "a political show" that "would not be very productive."

Putin did not explain Friday why he changed his mind.

Public opinion polls have revealed deep dissatisfaction with Russia's security services. In the week before the Beslan carnage, apparent suicide bombings downed two jetliners and another bomb exploded outside a Moscow subway station, killing a total of 100 people.

Putin announced the decision in a scripted, televised meeting with a top ally, Sergei Mironov, chairman of the Federation Council. "We're all interested in getting the full and objective picture of all the tragic events related to the hostage taking in Beslan," Putin said. "I gave orders to law enforcement agencies and talked to the prosecutor general so they provide all the necessary documents, all the necessary information to the commission."

The Federation Council, whose members are appointed by regional governments, rarely plays a prominent role in Russian politics. While the lower house, the State Duma, initiates legislation and debates treaties, the Federation Council normally just follows suit, approving whatever is submitted by the Kremlin.

Some Russian analysts said Putin's choice of an appointed parliamentary body rather than the elected chamber was likely intended to keep the process under control while giving the appearance of accountability. Igor Trunov, an attorney representing victims of the Moscow theater siege who sued the government in an attempt to uncover the facts of the incident, called it a half-step forward.

"It looks like some lessons are being learned from the mistakes of the past," he said. But "the Federation Council is a completely controlled establishment and has only shown loyalty to authorities. That's why the word 'independent' could never be used."

The Russian government has traditionally employed secrecy and deception in responding to major tragedies, and it has followed that pattern in the past two weeks.

After the two near-simultaneous plane crashes, authorities discounted terrorism and tried to blame them on human or technical error, an implausible claim finally disproved by traces of explosives found at the scenes.

In the Beslan siege, the government has acknowledged deliberately underestimating the number of hostages initially by two-thirds. Officials claimed 10 Arabs were among the hostage takers, but as of Friday none had been identified among the dead. Many relatives contend Moscow is still understating the death toll.

Mironov did not say whether he would delve into such sensitive topics. But even if conducted by Putin's allies, the inquiry could provide a forum for critics to question how the guerrillas were able to get into the school and how security forces handled the 52-hour siege. Putin has indicated dissatisfaction with security agencies and could use the investigation to justify a shake-up.

Russia continued to inveigh Friday against the United States and Britain for granting asylum to Chechen separatist leaders in the past. Hundreds of protesters organized by a nationalist party close to the Kremlin gathered outside the U.S. and British embassies.

Secretary of State Colin L. Powell tried to calm the dispute, noting in an interview in Washington with the Associated Press that the U.S. asylum had been granted by a court.