Swiss commodities trader Glencore said it is selling a major part of a stake it only recently acquired in Russian oil giant Rosneft to Chinese conglomerate CEFC

Russian state oil giant Rosneft said Tuesday that its servers had suffered a "powerful" cyberattack, but insisted that production had not been hit.

"A powerful hacking attack has been carried out against the company's servers," Rosneft said on Twitter.

The firm added that it "hopes" the incident was "not connected to current legal proceedings".

Rosneft is currently suing private firm Sistema for 170 billions rubles (2.55 billion euros, $2.88 billion) over the state giant's acquisition of oil company Bashneft.

Russia's leading oil producer said the attack "could have had serious consequences" but said that thanks to a back-up system "the production and extraction of oil were not stopped."

A court on Tuesday announced a halt in the case between Rosneft and Sistema -- owned by tycoon Vladimir Yevtushenkov -- until July 12. There was no immediate comment from Sistema on the reported cyberattack.

Hacking in Russia is currently in the spotlight after the US alleged Moscow was behind attacks during its presidential campaign last year.

There is no evidence that the alleged attack on Rosneft was linked to international tensions.

Major Russian state-run firms have suffered repeated cyberattacks in the past.