France deployed 45,000 police officers and some armoured vehicles to the streets on Saturday as riots rocked French cities for a fourth night after an officer shot dead a teenager during a traffic stop.

Buildings and vehicles were torched and shops were looted, and the violence has plunged President Emmanuel Macron into his most serious crisis of leadership since the Yellow Vest protests began in 2018.

The unrest has spread across the country, including in cities such as Marseille, Lyon, Toulouse, Strasbourg and Lille, as well as Paris, where 17-year-old Nahel M, of Algerian and Moroccan descent, was shot dead in a Nanterre suburb on Tuesday.

His death, captured on video, has rekindled long-standing complaints of police violence and racism in poor and racially mixed urban communities.

Interior Minister Gerald Darmanin said on Saturday morning that 270 people had been arrested since the unrest broke out on Friday night, bringing the total to more than 1,100.

Friday night’s arrests included 80 people from the southern city of Marseille, which is France’s second-largest city and home to many people of North African descent.

Social media images showed an explosion in the old port area of Marseille. City officials said they were investigating the cause but did not believe there were any casualties.

Police said rioters looted a gun shop in central Marseille and stole some hunting rifles, but no ammunition. Police said a man has been arrested with a rifle possibly from the store. The shop was now guarded by the police.

Marseille’s mayor, Benoît Payen, called on the national government to immediately send additional troops. “The scenes of looting and violence are unacceptable,” he said in a tweet late on Friday.

Three police officers were slightly injured in the early hours of Saturday. A police helicopter flew overhead.