Some of Ukraine’s major institutions have been among the targets of a huge cyber attack.

Deputy Prime Minister Rozenko Pavlo said he and other members of the Ukrainian government were unable to access their computers.

“We also have a network ‘down’,” he wrote. “This image is being displayed by all computers of the government.”

The photo showed his PC displaying a message claiming a disk “contains erroers and needs to be prepared”, urging the user to to turn it off.

Ukrainian state-run aircraft manufacturer Antonov was among the companies hit, along with state power distributor Ukrenergo, which said the attack did not affect power supplies.

The National Bank of Ukraine said an “unknown virus” was to blame, saying several unnamed Ukrainian banks were affected along with financial firms.

“As a result of cyber attacks, these banks have difficulties with customer service and banking operations,” a statement said.

“The National Bank bank is confident that the banking infrastructure’s defence against cyber fraud is properly set up and attempted cyber attacks on banks’ IT systems will be neutralised.”

Computers and departure boards at Boryspil International Airport in Kiev were also down.

Oschadbank, one of Ukraine’s largest state-owned banks, said some of its services had been affected by a “hacking attack” but guaranteed that customer data was safe.

The Ukrposhta state postal service, television stations and Kiev’s metro system were also affected.

Rosneft, a Russian government-owned oil firm, said it was also targeted by a “massive hacker attack” on its servers, as was steel maker Evraz.

Written by Andrew Holt