The attack started around 7 p.m. when the armed man went into the San Isidro church and assaulted a priest, who was seriously injured, the ministry said.
The assailant then went to a second church, the Nuestra Señora de La Palma — a five-minute walk away — where he entered and continued his rampage, assaulting the sexton. The sexton, whose job it is to take care of the church and its maintenance. fled outside where the attacker dealt him the mortal wounds in a public square, the ministry said.
The Algeciras town hall said the sexton was named Diego Valencia and identified the wounded priest as Antonio Rodríguez. The town hall said he was hospitalized and in stable condition.
Local media reported that at least three other people were injured.
Spain’s National Court said a judge has opened an investigation into a possible act of terrorism.
Police are investigating the incident, the interior ministry said, to determine the “nature of the attack.” It offered no further detail on the attacker’s possible motive.
Spanish Prime Minister Pedro Sánchez joined the outpouring of condolences.
“I want to express my sincerest condolences for the families of the sexton slain in the terrible attack in Algeciras,” Sánchez wrote on Twitter. “I desire the injured a swift recovery.”
The secretary general of Spain’s Episcopal Conference, Francisco García, wrote on Twitter that “I have received the news of the incident in Algeciras with great pain.”
“These are sad moments of suffering, we are united by the pain of families of the victims and for the Diocese of Cádiz,” he added.
Algeciras is near the southern tip of Spain, resting across from a bay from Gibraltar. It is home to an important port with ferry connections to northern Africa.
The town hall declared a day of mourning when flags will fly at half-staff.
“We are all stunned by these acts, which have filled us with pain,” Mayor José Landaluce said. “Algeciras has always been a city where concord and tolerance reign, despite incidents like this that create an image that does not correspond to reality.”