Police officers stand guard near Notre Dame church in Nice, southern France, Oct 29, 2020. An attacker armed with a knife killed at least three people at a church in the Mediterranean city of Nice, prompting the prime minister to announce that France was raising its security alert status to the highest level. (ERIC GAILLARD / POOL VIA AP)

PARIS - A judicial source said a 47-year-old man had been taken into custody on Thursday evening on suspicion of having been in contact with the perpetrator of an attack during which three people were killed in a church in the French city of Nice.

France is engaged in a war against Islamist ideology and more militant attacks on French soil are likely, the interior minister said on Friday

A knife-wielding attacker shouting “Allahu Akbar” (God is Greatest) beheaded a woman and killed two other people the church attack on Thursday before being shot by police and taken away.

France is engaged in a war against Islamist ideology and more militant attacks on French soil are likely, France's Interior Minister Gerald Damarnin said on Friday.

“We are in a war against an enemy that is both inside and outside,” Damarnin told RTL radio. “We need to understand that there have been and there will be other events such as these terrible attacks.”

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Chief anti-terrorism prosecutor Jean-Francois Ricard said the man suspected of carrying out the attack was a Tunisian, born in 1999, who had arrived in Europe on Sept 20 in Lampedusa, the Italian island off Tunisia that is a main landing point for migrants from Africa.

A Tunisian security source and a French police source named the suspected attacker as Brahim Aouissaoui. Ricard said the suspected attacker had entered the city by train early on Thursday morning.

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The suspect was in hospital in critical condition, he said.

The Nice attack occurred just under two weeks after a school teacher in a Paris suburb was beheaded by an 18-year-old attacker who was apparently incensed by the teacher showing a cartoon of the Prophet Mohammad in class.