NICE - It was by a stroke of luck that Singaporean student Mr Huang Jing Jie, who was at the Promenade des Anglais in the southern French city of Nice, decided to leave five minutes before fireworks ended on Bastille Day, he said.

Shortly after he left with his friend, a truck ran through crowds celebrating the occasion, killing 84 and injuring dozens more.

Mr Huang, 23, an engineering product development student at the Singapore University of Technology and Design (SUTD), had been with a schoolmate when the incident took place.

Some of his schoolmates were scattered around the promenade.

The 12 SUTD students had left for a three-week summer programme that started on July 3, and were due to return to Singapore next week.

In the group, there were seven Singaporeans including Mr Huang, two permanent residents, one Vietnamese, one Indonesian. There was also a Malaysian student, who was injured.

"I was watching the fireworks on Bastille day at the promenade," he told The Straits Times. "But by some stroke of luck, my friend and I decided to leave five minutes before the fireworks ended."

They wandered into a church shortly after, but the doors slammed shut in minutes.

"We found a lot of people crying inside," he said. "We hid in the church for about 20 minutes before they opened the doors."

Unsure of what happened, most people thought that there were gunmen shooting in the crowd.

Mr Huang and his friend then joined the crowd: "People were running and crying."

They rushed back to their hostel, he added, which was 30 minutes away. There, the students did a rollcall.

But Mr Esmond Chuah, 22, was not there.

"We knew he went to the beach so we were quite worried that something might have happened to him," said Mr Huang. "But we couldn't contact him at all... someone told us that they saw Esmond going into an ambulance."

They only heard from him the next day when Mr Chuah contacted the group through a nurse's phone, and they visited him at the hospital.

The group is mostly "relieved" now, worried for Mr Chuah, and are likely to be proceeding with their original plans, said Mr Huang.

Mr Chuah remains in the hospital - he had injured his back and cannot move excessively.

Meanwhile, France is in mourning and the promenade is under lockdown.

"Ambulance sirens can still be heard quite frequently even until now," Mr Huang said. "There're a lot fewer people on the streets now."