Major firms across Europe have been hit by a massive cyber attack, a media report said.
In Ukraine, government departments, the central bank, a state-run aircraft manufacturer, the airport in Kiev and the metro network have all been paralysed by the hack, the Telegraph reported.
In Britain, the advertising firm WPP said its systems had been struck down while in the Netherlands a major shipping firm confirmed its computer terminals were malfunctioning.
The virus is believed to be ransomware — a piece of malicious software that shuts down a computer system and then demands an extortionate sum of money to fix the problem, the daily said.
It comes after the WannaCry hack in May which affected more than 150 countries and crippled parts of the Britain's National Health Service.
"The National Bank of Ukraine has warned banks… about an external hacker attack on the websites of some Ukrainian banks… which was carried out today," Ukraine's central bank said in a statement.
A spokesman for Ukraine's Presidential Administration said it was paying "a high level of attention" to the situation.
Maersk, a Dutch transport and logistics company, announced that "multiple sites and business units" had been shut down after a cyber attack, BBC reported.
It came as Russian oil giant Rosneft said its servers had suffered a "powerful" cyberattack.
Spanish media reported that the offices of large multinationals such as food giant Mondelez and legal firm DLA Piper also suffered attacks.
French construction materials company St. Gobain said it had also fallen victim.
Reports said the Kiev metro system stopped accepting payment cards while several chains of petrol stations suspended operations.
Ukraine's Deputy Prime Minister Pavlo Rozenko tweeted a picture of a computer screen showing an error message.
"We also have a network 'down'," Rozenko said on Facebook. "This image is being displayed by all computers of the government."