Police have arrested four men in connection with a series of explosions at Polish supermarkets.

The public prosecution service said the suspects, aged 20 to 26 and all from Amsterdam, had been detained during May as part of the investigation. A 19-year-old man who was arrested and released in January remains a suspect.

The public prosecution service said the youngest of the four suspects was arrested in France on a European arrest warrant and handed over to Dutch authorities.

The stores in Aalsmeer, Heeswijk-Dinther, and Tilburg, as well as two in Beverwijk, were hit by bomb blasts in December and January. Three of the stores were owned by the same family.

The prosecution service and the insurers of the business premises put up a total reward of €50,000 for information to help solve the crime.

Nobody was injured in the explosions, but an 88-year-old woman who had to be evacuated from her house near one of the bomb sites was later taken to hospital.