Two Americans were killed in an attack in Nice, France, Thursday night, after a driver plowed into a large crowd with a truck hauling grenades and other weapons during Bastille Daycelebrations, the U.S. State Department said.
Officials did not name the two Americans, although family members confirmed their identifies to ABC News.
"We are aware that two U.S. citizens were killed in the attack. We are working with local authorities to determine if other U.S. citizens were injured in the event," according to a statement released by the State Department this morning. "We strongly urge U.S. citizens in Nice to be in direct contact with your family members in the United States and elsewhere to advise them of your safety."
Sean Copeland and his 11-year-old son Brodie, who were in Nice on a family vacation, were killed in the attack, Alyssa Weaver, the elder Copeland's niece, wrote on Twitter. The Copelands are from Lakeway, Texas, about 30 miles west of Austin.
Weaver tweeted, "I am asking for prayers for my family, due to the tragedy in Nice, France I lost my uncle Sean and my 11 year old cousin Brodie I ask for prayers for my aunt Kim and my two other cousins Maegan and Austin during this tough time and prayers for my family’s safe trip back home #CopelandStrong”
The death toll climbed overnight from 80 to 84 people, including several children, as dozens more were injured and receiving treatment, according to the Ministry of the Interior.
"France is horrified by what has just occurred -- a monstrous act of using a truck to intentionally kill dozens of people celebrating 14th of July," French President Francois Hollande said during a nationally televised address early today. "France is strong. France will always be stronger than the fanatics who want to strike France today."
Officials have not yet identified the attacker, and there have been no claims of responsibility. The Paris anti-terrorism prosecutor's office was put in charge of the investigation.
Hollande extended the country's state of emergency for three months and was mobilizing reservists. He said it was unclear whether the attacker had any accomplices.