The Andalusians had scored their first goals at Los Carmenes in three matches to come from behind and lead the islanders 2-1 with just under half an hour to play.
But the match officials then took the decision to suspend the game after the referee's assistant was struck with an object thrown from the stands after 63 minutes.
Spanish national news agency EFE reports the assistant was hit by an umbrella that opened a wound in his cheek and that the fan who threw the object has been detained by the police.
If and when the match will be resumed remains unclear.
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