VTB, the state-owned, second largest bank in Russia, has reported the largest cyberattack in its history.

Officials said the bank was repelling the distributed denial of service (DDoS) attack, in which hackers attempt to flood a network with unusually high volumes of data traffic in order to paralyse it.

VTB said access to its mobile app and website could be hindered. Russian government entities and state-owned companies have been targeted over events in Ukraine

Websites of the Kremlin, flagship carrier Aeroflot and major lender Sberbank among those to have seen outages or temporary access issues.