Firms around the globe are reporting that they have been hit by a major cyber-attack.
British advertising agency WPP is among dozens of firms reporting problems.
Ukrainian firms, including the state power distributor and Kiev’s main airport were among the first to report issues.
Some experts are suggesting that it could be a ransomware attack, similar to Wannacry which hit last month.
Alan Woodward, a computer scientist at Surrey University, said: “It appears to be a variant of a piece of ransomware that emerged last year.