The Islamic State claimed responsibility for Thursday’s truck attack in Nice, France, alleging that the assailant Mohamed Lahouaiej Bouhlel was a “soldier” of the group, the New York Times reports.

The mayor of Nice’s office has identified the driver in Thursday’s attack as Mohamed Lahouaiej Bouhlel, a 31-year-old Frenchman of Tunisian descent, NBC News reports. His identity card was found in the truck.

On Thursday night, Donald Trump announced on Twitter that he was rescheduling a press conference to reveal his vice presidential pick originally slated for Friday morning due to the recent attack in Nice, France.

According to French officials, at least 80 people are dead and 18 are in critical condition in Nice, France, after a driver plowed a truck through a crowd during a Bastille Day parade, the BBC reports. French President Francois Hollande said the attack was of a “terrorist nature.”