Yandex, the country’s leading search engine, has announced plans to stop ranking popular blog posts after several entries exposed problems that embarrassed government officials.

The looming change stirred fears Thursday about a crackdown on free speech on the country’s No. 1 search engine.

Yandex explained in a statement that the rating service, dubbed Top Yandex, had stopped reflecting the situation in the Russian blogosphere and instead become a “media tool” aimed at influencing the public and the mass media.

Unscrupulous parties charge fees to boost blog posts to the top of the top 10 list, the statement said.

“The rating was created as a mirror of the blogosphere … but it has become a tool of influence,” Anton Volnukhin, the head of Yandex’s blog search service, said in e-mailed comments.

Bloggers often have used Top Yandex, which reflects the most quoted and discussed topics in the Russian blogosphere, to decry social problems and appeal to the public and mass media for help. Bloggers ask one another to repost messages in order to climb up the Top Yandex list, which is found on the search engine’s homepage.

The rating system has helped to expose stories that have embarrassed the government and forced it into action. The most recent example involved a Pskov region nursing home where employees neglected the elderly residents. A group of volunteers working there complained on LiveJournal, prompting widespread media coverage and a public outcry that caused regional authorities to dismiss the director and close the nursing home. President Dmitry Medvedev mentioned the nursing home this week at a meeting on social services.

Top Yandex is also used by charity groups to collect money for urgent operations, while nationalist and extremist issues have surfaced there as well.

Some Internet insiders said Yandex’s statement contained a hint that the decision to close the rating system was politically motivated.

“If you don’t want to be manipulated, you have no choice but to shut down,” said Anton Nosik, a pioneer of the Russian Internet and the former president of No. 2 search engine Rambler.ru.

“This is the usual fate of independent media,” he said.

Yandex denied politics had played a role.

Top Yandex was set up on Oct. 4, 2006, and is to close next month.

The issue of Top Yandex’s closure climbed up the rating list Thursday. Some bloggers said the change would not make much difference, while others worried that it would limit free speech. An open letter has been posted asking Yandex to backtrack on its plans.

“I think Yandex just wants to protect its reputation and the decision doesn’t have any political background,” said Ilya Yashin, a member of the Solidarity opposition movement and a blogger.

Yashin said the closure would not hurt free speech.

 “Bloggers are sneaky and will find other ways to report information to the mass media,” he said.

Many politicians have opened their own blogs this year, including President Dmitry Medvedev and State Duma Speaker Boris Gryzlov, both on LiveJournal.

Their blogs get a lot of attention in the mass media, but they attract less online interest than those ranked on Yandex’s list.

A spokeswoman for the Kremlin’s Internet department said Thursday that she was aware of the changes planned by Yandex. She did not elaborate.

The spokeswoman did say, however, that Medvedev’s blog has made the Top Yandex list a total of 22 times this year.