[BBC] – Russia’s Economy Minister Alexei Ulyukayev has been accused of taking a bribe to endorse a state takeover. Russia’s main anti-corruption body, the Investigative Committee (SK), said he received a payment of $2m (£1.6m).

Mr Ulyukayev is the highest-ranking Russian official held since the 1991 coup attempt in what was then the USSR. The SK said he had “threatened” to create obstacles for Rosneft’s operations when it took a 50% stake in another state oil company, Bashneft.

The minister pleaded not guilty to the bribe charge and saw his arrest as “an act of provocation against a state official”, his lawyer said. According to SK spokeswoman Svetlana Petrenko, “Ulyukayev was caught red-handed”, receiving a $2m bribe on 14 November for giving a favourable assessment of the Rosneft deal. Investigators asked the court to place him under house arrest, Interfax reported.

Mr Ulyukayev’s deputy Yevgeny Yelin was appointed later on Tuesday as acting economy minister.

The apparent sting operation came after months of electronic surveillance, including phone-tapping, officials said. Unconfirmed reports said the internal FSB security service had run the entire operation.

The arrest was big news on Russia’s state-run TV channels.

However, sources told the Novaya Gazeta website that Mr Ulyukayev himself did not take any money, contradicting earlier reports, and there was no video footage of his arrest.

The economy ministry described the arrest as “strange and surprising”.

Alexander Shokhin, the head of the Russian union of industrialists and entrepreneurs, told Russian radio he had serious doubts about the arrest.

“You would have to be insane, a month after the deal got legal and political approval, to threaten Rosneft and extort $2 million from [Rosneft Chief Executive] Igor Ivanovich Sechin, who is actually one of the most influential people in this country.

“You have to think Ulyukayev has spent 25 years in politics and they’re portraying him like some kid who acts in that field like a complete novice.

“It’s hard to tell who’s actually gaining from all this, apart from the SK which is diverting attention away from their generals who are being investigated.”

If found guilty, Mr Ulyukayev, 60, could face a prison sentence of between eight and 15 years. An economic liberal in the 1990s, he became deputy chairman of Russia’s central bank in 2004. He was appointed economy minister in 2013.

It was only in October that Rosneft, an oil giant controlled by the Russian government, bought 50% of Bashneft for 330bn roubles ($5bn). Bashneft itself was one of Russia’s largest state oil companies.