A third person was taken into custody in France in connection with a knife attack which left three dead in Nice on Thursday, a police source said on Saturday, as the government ramps up security efforts against possible militant attacks.
An assailant shouting "Allahu Akbar" (God is Greatest) beheaded a woman and killed two other people in a church in Nice, in France's second deadly knife attack in two weeks.
The third arrest took place on Friday and followed another that day and a previous one on Thursday, the police source said. At least two of the people in custody, including one Nice resident, were being investigated over suspected contacts with the attacker, judicial sources have said.
The suspected assailant was shot by police and is now in critical condition in a hospital.
President Emmanuel Macron has deployed thousands of soldiers to protect sites such as places of worship and schools, and ministers have warned that other Islamist militant attacks could take place.
The Nice attack, on the day Muslims celebrate the Prophet Mohammad's birthday, came amid growing Muslim anger across the world over France's defence of the right to publish cartoons depicting the prophet.
On Oct. 16, Samuel Paty, a school teacher in a Paris suburb, was beheaded by an 18-year-old Chechen who was apparently incensed by the teacher showing a cartoon of the Prophet Mohammad in class.
Protesters have denounced France in street rallies in several Muslim-majority countries, and some have called for boycotts of French goods.
An interview with Macron on the TV network Al Jazeera, in which he addresses some of these tensions, is due to air later on Saturday, the French president's office said.
By reaching out directly to Muslim audiences, Macron is keen to counter what he sees as a misinterpretation of his recent statements on Islam and explain France's often misunderstood secularist model, people close to him said.
Macron also spoke to Pope Francis on Friday, following the attack at the Notre-Dame Catholic basilica in Nice, the President's office said, and discussed the importance of freedom of speech and of dialogue between religions.
"He (Macron) stated he would continue to fight against extremism so that all French people can express their faith in peace and without fear," his office said.
France's chief anti-terrorism prosecutor has said the man suspected of carrying out the Nice attack was a Tunisian born in 1999 who had arrived in Europe on Sept. 20 in Lampedusa, the Italian island off Tunisia.
Prosecutors in the Sicilian city of Palermo, in Italy, are investigating the man's subsequent passage through the island, including the people he might have been in touch with there, and are requisitioning phone records, judicial sources told Reuters.
Investigators are looking into the possibility that the suspect arrived in the Italian city of Bari in early October, on a ship used to quarantine migrants, before leaving for Palermo, the sources said.