MOSCOW, June 27. /TASS/. Neither the Kremlin website nor its computer systems have been affected by today’s hacker attack, Russian president’s press secretary Dmitry Peskov told TASS on Tuesday.

"Everything is operating routinely," he said.

Group-IB, a company dealing with prevention of and investigation into cybercrimes, said on Tuesday a Petya ransomware virus attacked a number of companies, such as Rosneft, Bashneft, Mars, Nivea and Mondelez International (manufacturer of Alep Gold chocolates).

The Petya virus infects computer files and extorts a $300-bitcoin ransom to unblock them. According to Group-IB specialists, this virus has been recently used by the Cobalt group to hide traces of its attack on financial institutions.

The latest large-scale attack on computers of Russian companies and government institutions was staged on May 12, when unidentified hackers tried to attack Windows OS computers in 74 countries with a WannaCry ransomware virus that extorted a $600-bitcoin ransom to unblock them. According to the Russian cybersecurity and anti-virus provider Kaspersky Lab, a total of 45,000 cyber attacks were carried out across the world. Most of the attempts at infecting computers were registered in Russia.

Some reports said that they used a hacking tool developed by the US National Security Agency.