Spanish authorities said they were investigating a possible "terrorist" in which a man attacked several people with a machete in two churches in the southern port town of Algeciras, killing at least one person.
The man attacked clergymen at two different churches -- San Isidro and Nuestra Senora de La Palma, around 300 metres apart -- just after 8pm on Wednesday evening in central Algeciras, a spokesperson for the city reported.
The suspect's name and nationality have not yet been declared. Local media, including El Pais newspaper, have claimed he is a 25-year-old Moroccan.
A source at Madrid's High Court said the incident was being investigated as terrorism.
The man who was killed was Diego Valencia, a sacristan at the Nuestra Senora de La Palma church, while the titular priest of the parish church of San Isidro, Antonio Rodriguez, is among the injured and in critical condition, Algeciras spokesperson said.
Police claim the assailant first entered the San Isidro church and attacked Rodriguez. A statement by the Algeciras Salesians said Rodriguez, 74, had been celebrating Eucharist when he was attacked.
The suspect then went into the Nuestra Senora de La Palma church where he damaged property before attacking Valencia, who fled the church but was chased before being killed, police said in a statement.
An unknown number of others were also injured, with El Mundo newspaper reported that four people had been wounded.
The parish priest at Nuestra Senora de La Palma, Juan Jose Marina, told broadcaster SER the suspect went straight for Valencia after the mass had finished, suggesting he might have thought Valencia was the priest.
"Possibly, this death was meant for me and it found him instead," a tearful Marina said.
Spanish Prime Minister Pedro Sanchez expressed his condolences to the victims of the "terrible attack" on Twitter, while the secretary general of Spain's Episcopal Conference, Francisco Garcia, noted his "great pain" on hearing the news.
"These are sad times of suffering, we are united by the pain of the victims' families and for the Cadiz Diocese," he tweeted.
Jose Ignacio Landaluce, the mayor of Algeciras, has declared a day of mourning in the city for Thursday and a rally outside Nuestra Senora de La Palma church at midday.