MOSCOW — Russian presidential hopeful Ksenia Sobchak urged President Vladimir Putin on Thursday to seek a full investigation of one of the country’s worst hostage crises, but stopped short of blaming him for the deadly raid that ended the standoff 15 years ago.

Sobchak, a socialite and opposition-leaning TV star who announced her candidacy last week, laid flowers outside the theater where Russian special forces ended a 57-hour siege by Chechen rebels on Oct. 26, 2002. She made comments portraying Putin as a bystander to the events.

The siege was widely seen as one of the darkest moments of Putin’s presidency. Many Russians blamed Putin for the heavy death toll among the hostages when Russian special forces stormed the Dubrovka Theater.

The 41 hostage-takers were killed, but so were at least 127 of the hostages who died from the effects of a narcotic gas that special forces pumped into the building to knock out the militants. Two more died from gunshot wounds.

Relatives say many of the victims died because they were denied medical help and accuse the Russian government of covering up its role in the carnage. Authorities have consistently refused to disclose the contents of the gas, angering survivors and victims’ relatives.

“I think that everyone who took part in this operation is responsible,” Sobchak told The Associated Press. “There are many questions, and I think that Vladimir Putin must urge the people who were in charge of the assault to conduct a full public investigation.”

Sobchak started out as an entertainment TV presenter before joining anti-government protests in 2011 and working for a major independent TV outlet. She is the daughter of former St. Petersburg mayor Anatoly Sobchak, who was Putin’s mentor before Putin moved to Moscow.

Many in the Russian opposition are suspicious that Sobchak’s candidacy is an attempt by the Kremlin to further divide the fractured opposition.

Sobchak has said that she met Putin and told him about her plans to run, but she denies being a Kremlin stooge. The most visible opponent of Putin’s government, Alexei Navalny, wants to run in the election in March but is legally barred from doing so.

Putin hasn’t yet said whether he will seek re-election in the March 18 presidential vote, but he’s widely expected to run.

The Russian leader’s approval ratings — now topping 80 percent — all but guarantee a landslide victory in a field that also includes stolid veterans from past races. However, the government has been worried about growing voter apathy.