RussNeft President Mikhail Gutseriyev was charged with illegal business practice and tax evasion, the Interior Ministry said Tuesday.

"May 4, the Interior Ministry Investigations Committee charged Mikhail Gutseriyev, president of the RussNeft oil company, under the provisions of Article 171/2 of the Russian Criminal Law Code (illegal business activity committed as an organized group)," the ministry press service said.

The Investigations Committee said in January it had launched a preliminary investigation into RussNeft on suspicion of large-scale tax evasion.

A few days prior to that, RussNeft offices had been searched and Gutseriyev questioned as a witness.

He faces up to six years in prison if convicted.

Gutseriyev denied any charges have been formally brought against him.

"The charges were presented to my executives or vice presidents," he said.

He said the allegations apparently concerned a 'surplus' 60,000 metric tons of oil produced by a company subsidiary, adding that next to the 15 million tons of its annual output, it was a very small amount.

RussNeft had no comment.

Gutseriyev is 31st on the Forbes list with a personal wealth of $3 billion.

According to the business daily Vedomosti, Gutseriyev's problems stem from his conflict with the Kremlin and the reluctance to sell his company. He set himself on a collision course with the Kremlin by buying some of the embattled oil company Yukos' assets shortly before it was declared bankrupt.

The daily quotes informed sources as saying that last year Gutseriyev received an offer to sell his company for $1 billion to a state controlled structure but turned it down, saying the price was ridiculous.

Experts put RussNeft at $8-10 billion.

RussNeft, Russia's newest vertically integrated oil company, is among the country's top 10 crude producers. Its recoverable reserves exceed 630 million metric tons (4.6 billion barrels).

(based on RIA Novosti and Vedomosti materials)