A man killed when he drove his car packed with arms and explosives into a police convoy in Paris had pledged allegiance to the leader of Islamic State, France's anti-terrorism prosecutor has said.
He also asked his family to remember him not as a suicide bomber but as a martyr, Paris prosecutor Francois Molins said.
Mr Molins, citing a letter written in the form of a will dated the day before the Monday attack on the Champs-Elysees Avenue, said the man had pledged his allegiance to IS leader Abu Bakr al-Baghdadi and practised shooting "to prepare for jihad".
The letter to his loved ones asked that his plan be treated not as a suicide attack but as a "martyrdom operation", Mr Molins said.
Mr Molins said the attacker, whom he identified only as Adam D, had a huge cache of weapons both at home and in the vehicle he drove.
Evidence from the investigation shows the suspect wanted to join IS forces in Syria and Iraq, the prosecutor said.
The attack was aborted when the car exploded after the driver rammed the lead car in the police convoy, killing himself, Mr Molins said.
Police jumped out of the vehicle, ran to the car, smashed its windows and pulled out the driver in an apparent attempt to save him.
Police officials earlier identified the suspect as 31-year-old Adam Djaziri.
He was born in Argenteuil, a Paris suburb, Mr Molins said.