Two Americans from Lakeway, Texas, were killed in France when a truck struck a crowd celebrating Bastille Day.
Sean Copeland, 51, and his 11-year-old son, Brodie, are among the at least 84 people killed in the apparent terrorist attack in Nice.
"We are heartbroken and in shock over the loss of Brodie Copeland, an amazing son and brother who lit up our lives, and Sean Copeland, a wonderful husband and father," Jess Davis, a family friend who is speaking for the family, said in a statement to the Washington Post. "They are so loved."
The State Department confirmed that two U.S. citizens were killed in the attack in the south of France, though it did not name the victims.
"We express our sincere condolences to the family and friends of those killed," spokesman John Kirby said in a statement. Kirby said the State Department is "providing all possible consular assistance."
The Copelands were on a family vacation that had taken them from Pamplona to Barcelona in Spain and then to the French Riviera city of Nice, Davis told the American-Statesman. Sean Copeland and his son Brodie were killed in the attack.
Kim Copeland, along with 29-year-old Maegan and 22-year-old Austin, survived, Davis told the Post. She said they are still in Nice.
On Twitter, family member Heather Copeland wrote of her heartbreak following the tragedy.
Another relative, Haley Copeland, wrote on social media that Sean and Brodie Copeland were on vacation with three other family members in Europe, celebrating a birthday.
"This is an extremely difficult time for my family and anyone who knows Sean and Brodie Copeland," she wrote. "Losing a loved one is hard no matter the circumstances but losing a loved one in such a tragic and unexpected way is unbearable. Prayers are much appreciated."
Brodie Copeland was a baseball player, and the Hill Country Baseball Club's Facebook page posted a photo of the 11-year-old on a beach - apparently in the French Riviera.
"Nobody deserves this type of fate, especially not such a wonderful family," the post read. "You are in our hearts, thoughts, and prayers. Rest in peace, Brodie and Sean, you will be remembered by many."
"Two of the greatest men," Bill Bishop wrote in a comment about the Copelands. "We will miss you. You will be missed but we know you were needed for bigger and better things."
He added: "It is hard to understand the loss but I am sure you two great men have been called and needed in a better place. You will be greatly missed but thanks for changing our lives while you were here. Stay strong Kim we are praying for you and we will see you soon."
The Pastime Training Center in Frisco, where Brodie played baseball, also posted a photo of him, writing: "One of our original PTC Aces players, Brodie Copeland, lost his life today along with his father Sean, in the attacks in Nice, France. Please keep their family in your prayers."
So far, there have been no reports of other American fatalities.
Kirby, the State Department spokesman, said the U.S. Embassy in Paris "is making every effort to account for the welfare of U.S. citizens in Nice. Any U.S. citizens in Nice should contact friends and family directly to inform? them of their well being."
The agency said Friday morning that it was still "working with local authorities to determine if other U.S. citizens were injured in the event."
Atlanta's NBC affiliate, WXIA, reported that 17 students from the Georgia Institute of Technology were in Nice to celebrate Bastille Day.
One of them, James Walker, said that he and his friends were facing the water after the fireworks show finished when suddenly the white truck zoomed past them from behind, narrowly missing them.
"The mirror of the truck came up and hit me on the head," Walker, an economics student who is studying abroad, told the news station. "I mean, I'm not hurt at all but that's pretty much how close I was to it."
Brendan Phillips, another Georgia Tech student who was with Walker, described the large crowd that ran towards them and his initial fears of a stampede.
"The entire crowd of people was running toward us," said Phillips, who is also studying abroad. "So my first thought was we're going to get stampeded by people. But we turned around, ran in the same direction."