Authorities suspect that the explosion was caused by “gender-based violent” violence.
Local officials report that the blast occurred near a playground for children in Orio, a town in the north.
Around 5.30pm, local time, a man and a woman were found dead in the fishing village.
No other victims were reported.
The explosion happened on a bench along a sidewalk.
According to police sources cited by EFE news agency, the initial investigation looked at a package that was held by one victim as the possible cause of the explosion.
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Inigo Ulkullu described the explosion, without providing more details, as “a tragic event that was allegedly caused by gender-based violent”
According to local media, Mr Urkullu asked for a moment of silence at a political rally.
Orio is a small town with a population of 6,000 people, located near the French border.