Dozens of supermarkets in Belgium and Sweden have been hit by a suspected cyber-attack affecting its refrigerators and freezers.

Around 40 Delhaize supermarkets in Belgium and Luxembourg were affected, while several ICA and Coop shops in Sweden were hit. Thirteen SuperValu shops have also been impacted in Ireland.

Millions of euros worth of food has had to be thrown away, according to local media reports, with one ICA store in Sweden saying temperatures for its freezers had been set to 50 C (122F).

It is not clear who is behind the attack, which follows a similar incident last month that affected hundreds of French supermarkets.

Both Belgium and Sweden's national cyber-security agencies said they were monitoring the incident.

Delhaize, one of Belgium's biggest supermarket chains, told Belgian media a "computer incident" had occurred overnight at 40 shops.

A Delhaize branch in Hoeilaart, in the Flemish Braband province in Flanders, told Het Laatste Nieuws it had lost €100,000 worth of produce.

The manager said that estimate did not even take into account further losses that would result from closing the shop.

Carrefour, a French-owned supermarket, said the incident had only affected 15 of its Belgian stores, adding that measures had been taken immediately to ensure all shops remained open.

Meanwhile, a spokesperson for ICA in Sweden confirmed the incident had affected a "small number of ICA stores operating outside ICA's central network".

"ICA is currently supporting the affected stores in managing the situation," they said.

One of the IVA branches located in Sjöbo, southern Sweden, wrote on social media: "Our refrigerators and freezers have been hacked overnight and they have set the temperature to 50 degrees."

The store was closed earlier but has now reopened to customers.

An employee at a branch in Odengatan in the capital Stockholm was pictured throwing away bags of spoiled food away.

Seven out of the 800 Coop stores in Sweden are also affected but the "situation is currently contained and under control", the company told the BBC.