Coop Sweden says it closed more than half of its 800 stores on Friday after point-of-sale tills and self-service checkouts stopped working.

The supermarket was not itself targeted by hackers - but is one of a growing number of organisations affected by an attack on a large software supplier the company uses indirectly.

Cyber researchers say about 200 businesses have been hit by this "colossal" ransomware attack, which had mainly affected the US.