(Reuters) - Three students on a study abroad program in France were wounded and another was missing in Thursday's Bastille Day attack in Nice, the University of California, Berkeley, said on Friday.

The university identified the missing student as Nicolas Leslie, 20, one of 85 Berkeley students on a 15-day study abroad trip on entrepreneurship in Europe. Two of the other students suffered broken legs and a third had a broken foot, the university said. The injured students were not identified.

"May Nicolas Leslie be found safe," the University of California's flagship campus posted on Facebook Friday, along with the hashtag #PrayforNice and the image of a heart painted like the tri-color French flag.

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

The Berkeley students were studying at a program affiliated with the international European Innovation Academy in Nice, the university said. The program was suspended temporarily as France marks three days of mourning, and students will be given the option of returning home early, the university said.

Leslie, a junior in the university's College of Natural Resources, was not listed among the dead in the attack, but family members have not been able to reach him, a woman who said she was a family friend said in an interview.

"The last thing that we heard from one of his friends is that he was seen running off," said the woman, who gave only her first name, Antonella.

Leslie, who was born in Italy and grew up in the San Diego area, was a U.S. national, university spokesman Roqua Montez said. The university did not yet have background information on the three injured students, he said.

In the attack, a man identified as Mohamed Lahouaiej Bouhlel plowed into a crowd of some 30,000 local people and tourists attending a fireworks display to celebrate Bastille Day.

At least 84 people were killed, 10 of them children, and 202 more were wounded.

French officials said Friday that Bouhlel, a 31-year-old Tunisian resident of Nice, was known to police for petty crime and violence, but had not been suspected of Islamist militancy.

In New York, site of the worst terrorist attack in U.S. history on Sept. 11, 2001, at the World Trade Center, Governor Andrew Cuomo ordered security tightened on mass transit and at airports, bridges and tunnels.

(Reporting by Sharon Bernstein in Sacramento, California; Additional reporting by Alex Dobuzinskis in Los Angeles; Editing by Toni Reinhold and James Dalgleish)