During Wednesday afternoon, a man entered the church of San Isidro, which is located in one of the city's most popular neighborhoods.
He then allegedly came into contact with the vicar and stabbed him.
He is said to have then attacked several people and at least one person has died in the attack.
The perpetrator was arrested shortly after the incident and is in national police custody.
The prosecutor of the National Court has announced that the incident is being investigated as a terrorist attack.
Juan Manuel Moreno, president of the Junta of Andalusia since 2019, has lamented the events via Twitter, describing the act as "terrible and heartbreaking".
"A sacristan has been murdered and at least one other priest has been injured in an attack that took place in Algeciras."
The text is updated.