A referee told players they would be sent off if they spoke Basque during a Spanish fifth-tier football match, according to reports.
The game between Elgoibar and Idiazabal was played in the Basque country, a region of Spain with its own language.
The region's culture and sports deputy, Denis Itxaso, said "the attitude of this referee can't be overlooked".
"These type of episodes do nothing but create a lack of respect towards the language and heritage," he added.
It is said the referee does not speak Basque and therefore did not want to miss players using insults.
Like Catalonia, the Basque country has a large degree of self-rule, its own language and cultural traditions.