France: A truck plowed into pedestrians during Bastille Day celebrations in the popular French seaside city of Nice Thursday, leaving at least 80 people dead in what the nation’s president called “obviously a terrorist attack.”

The deadly toll, which included several children, came after the truck slammed into revelers gathered on a promenade to watch fireworks, France President Francois Hollande said in an address Friday morning.

“Such a monstrosity,” Hollande said. He pledged to step up efforts to fight terror in Iraq and Syria, and said he will seek to extend a state of emergency by three months.

“France is deeply saddened, but it is also very strong,” Hollande said. “I can assure you we will always be stronger than the fanatics who are trying to attack us.”

The driver was fatally shot by police, Hollande said. It is unknown if there were accomplices, Hollande said. French media, citing a police source, reported that ID papers belonging to a French-Tunisian were found in the truck. A source that the driver is believed to have been a French national of Tunisian descent

The truck struck the crowd at around 10:40 p.m. local time (4:40 p.m. ET) shortly after a fireworks display, officials and witnesses said.