Four individuals were in custody on Sunday following a fatal stabbing in eastern France, an attack authorities have linked to Islamic extremism, The Associated Press reported, citing the national anti-terrorism prosecutor’s office.

The incident took place on Saturday in the city of Mulhouse, near the German border, resulting in the death of a Portuguese man. Seven police officers sustained injuries, including a parking control agent who was hospitalized with serious wounds, the prosecutor’s office reported.

Among those detained was the suspected attacker, a 37-year-old Algerian man identified as Brahim A. by prosecutors. The interior minister described him as an Islamic extremist with a schizophrenic profile. Authorities also detained two of his family members and an individual who had provided him lodging.

French President Emmanuel Macron emphasized the government’s “complete determination” to address the attack, which he attributed to “Islamist terrorism.”

During the assault, the suspect repeatedly shouted “Allahu akbar”, according to the prosecutor. He was armed with both a knife and a screwdriver.

The suspect initially arrived in France without documentation in 2014. He was later arrested and convicted of glorifying terrorism following the Oct. 7, 2023, Hamas attack on Israel, Interior Minister Bruno Retailleau stated on Saturday night.

After serving several months in prison for that conviction, the suspect was placed under house arrest while authorities attempted to deport him to Algeria.

France has been on high alert in the wake of terrorist attacks in recent years. The country was hit by a series of Islamist attacks, including the January 2015 attacks on the satirical newspaper Charlie Hebdo and the Jewish Hyper Cacher supermarket in Paris.

In November of that year, 130 people were killed in a series of jihadist attacks in Paris claimed by the Islamic State (ISIS).