An Islamic State video shows what it says is the young Chechen-born man accused of Saturday's deadly terrorist knife attack in downtown Paris.
French police have identified the suspect as Khamzat Azimov, who was a French citizen. He killed one person and wounded four before a police officer shot him dead.
An Islamic State outlet released the video showing a man it says is Azimov, wearing a hood with only his eyes exposed. He is speaking French and pledging allegiance to Islamic State.
IS had already claimed responsibility for the knifings, saying one of its "soldiers" carried them out to avenge France's participation in the international coalition in Iraq and Syria.
French authorities have taken Azimov's parents and a close friend into custody for questioning. Azimov was on the government's watch list of suspected terrorists, but had no criminal record.
Azimov was said to have been born in Chechnya, a Muslim-majority Russian republic, in 1997. He emigrated to France as a teenager, and grew up in Strasbourg.
Chechnya President Ramzan Kadyrov said the Russian republic bears no responsibility for Azimov becoming a killer.
"He was only born in Chechnya and his growing up, the formation of his personality, his views and persuasions occurred in French society," Kadyrov said.
Azimov carried out Saturday's attack in a district of Paris known for its fine restaurants and the famed Opera Garnier.
Witnesses say he yelled out "Allahu Akbar," meaning "God is great" in Arabic, and began stabbing people. Bystanders scrambled into restaurants and under tables for safety.
When Azimov rushed at police, an officer opened fire, killing him -- but not before one person was stabbed to death and four others -- including a Chinese tourist -- were wounded. Doctors say the four survivors are out of danger.
French police are treating this as a terrorist investigation. President Emmanuel Macron tweeted that France "will not yield an inch to the enemies of freedom."
On Sunday, the White House condemned the attacks, offering thoughts and prayers to the victims and their families, in a statement. "We stand in solidarity with the French people and their government against this vicious act of terrorism, and pledge any assistance needed," the statement said.
France is no stranger to deadly terrorist attacks claimed by Islamic State. They include the 2015 Charlie Hebdo killings, the murder spree later that year that started in a Paris concert hall, and the 2016 Nice truck attack.