Anger erupted on Tuesday after Nahel, 17, was shot at close range in Nanterre, a suburb west of Paris. Video posted on social media showed two police officers leaning into a car, with one of them shooting as the driver pulls away. Authorities haven’t released Nahel’s last name.

The police officer who fired the shot was referred for questioning as part of a murder investigation and is being held in detention.

“We believe that the legal conditions for the use of a weapon were not met,” Nanterre prosecutor Pascal Prache said at a press conference Thursday.

President Emmanuel Macron denounced Wednesday night’s violence, calling the acts “unjustifiable” in a tweet.

“Nothing justifies the violence that took place last night,” Prime Minister Elisabeth Borne said during a visit to the Val d’Oise department north of Paris, where a town hall was set on fire.

More than 6,000 people joined a march Thursday afternoon in Nanterre to protest the police killing. Some were hit by tear gas from police, televised images showed.

Authorities are significantly scaling up the number of security forces across the country as they prepare for further clashes. Bus and tramway service are suspended from 9 p.m. Thursday in the greater Paris area, regional president Valerie Pecresse said.

“We will do everything to ensure a return to order,” Interior Minister Gerald Darmanin said during a visit to a town hall in northern France that was targeted by protesters. “Arrests will be made tonight as soon as we see people trying to attack public buildings, police or local officials.”

The unrest has echoes of riots that broke out for weeks in 2005 after two boys died in an electricity substation following a police chase and throws a spotlight on French policing and long-simmering tensions in the country’s poorer suburbs.

An autopsy showed that Nahel was hit by a single gunshot that went through his left arm and thorax, Nanterre prosecutor Prache said.

A series of high-profile football stars, celebrities and political leaders have expressed outrage over the killing.

“A bullet in the head…It’s always the same people for whom being in the wrong leads to death,” French national team player Mike Maignan wrote on Twitter.