Yandex, the country's biggest Internet firm, plans to raise $1.5 billion to $2 billion in a New York IPO this fall, a source close to the offering said Tuesday.

The source said the proceeds expectations were based on a preliminary valuation of Yandex at $5 billion. He did not say what stake would be offered.

National media earlier reported that Yandex had mandated Morgan Stanley, Deutsche Bank and Renaissance Capital to organize an IPO on Nasdaq.

Yandex was founded in 2000 by Arkady Volozh and Ilya Segalovich, who own around 30 percent.

Yandex rival Google, meanwhile, is looking to improve its Russian performance, Google co-founder Sergei Brin said in an interview with Vedomosti published Tuesday.

Yandex receives about twice as many searches in Russia per day than Google, Brin said.

"We think our search is better, but [Yandex] also has many talented people," he said.