- Police identified Khamzat Azimov, 20 or 21, as the suspected attacker who killed one victim and injured four with a knife in Paris on Saturday.
- Azimov had been on a watchlist of suspected radicals since 2016, a French judicial source told the AP.
- French police fatally shot the suspected attacker and gathered his parents and friend for questioning, authorities said.
- The Islamic State group claimed responsibility for the attack and called the assailant a "soldier."
The 20-year-old Chechnyan suspect in a knife attack that left one man dead and others injured in Paris on Saturday had been flagged before as a security risk.
Authorities identified the attacker as Khamzat Azimov, a French citizen who was born in Chechnya, a federal republic of Russia in the south of the country.
Azimov was flagged as a suspected radical and national security threat since 2016, Reuters reported government spokesman Benjamin Griveaux said.
Police picked up Azimov's parents after the attack Saturday and took in a friend of his for questioning on Sunday, French judicial sources told the Associated Press.
Reports of Saturday's attack described a man wielding a knife and shouting "Allahu Akbar" ("God is greatest") before killing one man and injuring four others in central Paris, before police shot him dead.
The assailant had stabbed at the bystanders and then rushed at police shouting, "I will kill you, I will kill you!" police union representative Rocco Contero told Reuters. The attack occurred in Paris' Opera district, the BBC reported.
Counterterrorism officials are investigating the attack, and the Islamic State group has claimed responsibility and said the assailant was a "soldier" of the group, according to the Associated Press.
ISIS' Amaq news agency said in a statement that Saturday night's attack was in response to the extremist group's call for supporters to target allies of the US-led coalition to eliminate ISIS from Iraq and Syria.
Amaq also released cellphone video footage on Sunday that showed the attacker pledging allegiance to ISIS leader Abu Bark al-Baghdadi and calling upon followers in France, Germany, and the UK to carry out similar attacks.
French President Emmanuel Macron tweeted his thoughts for the victims and praised the police who "neutralized the terrorist." He also vowed that France would not give an inch to "enemies of freedom."
Prosecutor Francois Molins said authorities are investigating potential charges of murder and attempted murder in connection with terrorist motives.
"At this stage, based on the one hand on the account of witnesses who said the attacker cried 'Allahu akbar' (God is great in Arabic) while attacking passersby with a knife, and given the modus operandi, we have turned this over to the counterterrorist section of the Paris prosecutor's office," Molins told reporters, according to the Associated Press.
US President Donald Trump tweeted Sunday evening that he was "so sad" to hear news of the terror attack, and suggested that France should change the way it handles terrorism.
"At some point countries will have to open their eyes & see what is really going on," he said. "This kind of sickness & hatred is not compatible with a loving, peaceful, & successful country! Changes to our thought process on terror must be made."
The country has been on high alert for terror attacks in recent years, after a string of deadly ISIS-inspired massacres.
