75 Dead as Truck Plows Into Crowd in Southern France, Driver Killed (Video)

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, French 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 extended a state of emergency for 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 killed by police, Hollande said. It is unknown if anyone else was involved, he said.

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.

Christian Estrosi, president of the Provence-Alpes-Côte-d’Azur region that includes Nice, told French media that the driver also shot at people. A senior U.S. military official told NBC News that guns and explosives were found in the truck.

Eyewitness Andrew Botros described the scene as a “white truck literally racing through crowds of all ages.”

At the time of Hollande’s address, 77 people were confirmed dead. A short time later, French Minister of Interior Bernard Cazeneuve said the death toll had risen to 80, and 18 others were in critical condition.

U.S. President Barack Obama earlier condemned what he called “what appears to be a horrific terrorist attack” and said the U.S. has offered any assistance France may need. “We stand in solidarity and partnership with France, our oldest ally, as they respond to and recover from this attack.”

Witnesses described scenes of chaos after the truck hit the crowd.

“I looked up and saw, like, a tsunami wave of people just running towards me as fast as they possibly could screaming at the top of their lungs,” Dr. Kevin Motamedi, a Denver physician on a tour of Europe, told NBC News. “And I just grabbed who I was with and started running as fast as possible. It was basically just complete mass hysteria.”

“It was the scariest moment of my life, easily,” Motamedi said. “As we were running, you could tell the people in front of us had no idea that anything was going on, so we were running and grabbing people saying, ‘Run. Go home!’”

Eric Dratell, an American lawyer working in London, is in Nice on vacation with his wife. They were having dinner at Le Sporting on the beach when his wife heard what she thought was gunfire.

“We started running for cover. People started jumping from promenade level onto the beach,” Dratell told NBC News. “A guy jumped on my wife,” who was injured, he said.

“We took shelter with 200 or more people in an area under the promenade. People were in crowded toilet stalls,” Dratell said. “This is shocking,” he said.

In the immediate aftermath of the crash, Estrosi, who is also Nice’s former mayor, tweeted in French: “Dear Nicois, the driver of a truck appears to have made a dozens of deaths. For the moment, stay in your home. More info to come.”

France has been on edge since a series of coordinated terror attacks in Paris in November that left 130 people dead. The terror group ISIS claimed responsibility for that attack.

There were no immediate claims of responsibility by ISIS through its official or unofficial channels, according to Flashpoint Intelligence, an international terrorism research organization.

Hollande said he will be calling up operational reserves to help police, and the nation was placed at high alert. He said the country’s military campaign against the terror group ISIS in Iraq and Syria would increase.

“Nothing will shake us and make us renounce the fight against terrorism,” Hollande said.

France’s ambassador to the U.S., Gérard Araud, said on Twitter: “Again. Sadness. These people only wanted to enjoy Bastille day fireworks with their family and friends. Sadness.”

Canadian Prime Minister Justin Trudeau said: “Canadians are shocked by tonight’s attack in Nice. Our sympathy is with the victims, and our solidarity with the French people.”

Nice is a city on France’s Mediterranean coast popular with tourists. The U.S. State Department said it has no Thursday evening it had no information that any Americans were killed or injured.

Bastille Day, also known as National Day, commemorates the storming of the Bastille prison during the French revolution in 1789.

“On this Bastille Day, we are reminded of the extraordinary resilience and democratic values that have made France an inspiration to the entire world, and we know that the character of the French Republic will endure long after this devastating and tragic loss of life,” Obama said.