By Jon Herskovitz

AUSTIN, Texas (Reuters) - A Texan and his 11-year-old son on a family vacation were among at least 84 people killed when an attacker crashed a heavy truck through crowds celebrating Bastille Day in the French seaside city of Nice, officials said on Friday.

Texas Governor Greg Abbott named the two as Sean Copeland and his son Brodie. Sean, 51, and Brodie were from Lakeway, about 20 miles (30 km) northwest of Austin, and were in the southern Riviera city on a European vacation, family friend Jess Davis told the Austin-American-Statesman newspaper.

French President Francois Hollande called Thursday night's attack a terrorist act by an enemy determined to strike all nations that share France's values.

"Their family, like so many others, are devastated, are grieving: they need all the love and support of our American family as they grapple with unimaginable loss and try to get through what are going to be very difficult days," U.S. President Barack Obama said at an event in Washington, D.C.

Sean Copeland was the vice president of North and South America for Kapow Software, Davis said. Kapow is a division of Lexmark International Inc..

The French flag is being flown over the Texas governor's mansion in Austin in remembrance of the victims.

“While every heinous attack like this is tragic, this latest one hits close to home," Abbott said in a statement.

Brodie Copeland's fifth grade teacher described him as "a superstar."

"Whether in class, performing on stage or the baseball, he burst with talent," Coleen Serfoss told a news conference in Lakeway.

A photo of Brodie playing in French Riviera waters was posted on Facebook by his youth baseball league, Hill Country Baseball, which said it received it hours before the attack.

The post was followed by hundreds of comments, many offering condolences and prayers. Sean Copeland was remembered by several people in the baseball league as a loving and caring father.

A GoFundMe.com page was set up, seeking to raise $100,000 for the family.

Haley Copeland, a niece of Sean Copeland, wrote on Facebook that "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."

Three U.S. college students on a study abroad program were injured and another was missing in the attack in Nice, the University of California, Berkeley, said on Friday.

(Additional reporting by Brendan O'Brien, Barbara Goldberg in New York and David Brunnstrom in Moscow; Editing by Jeffrey Hodgson and James Dalgleish)