"After a fight between a French engineer and another who is Yemeni, the Frenchman - to enrage the Yemeni - threw a Quran on the floor in an offensive way," AFP reported one official as saying.
Helicopter set on fire
Yemeni employees then reacted by attacking the French employee and setting fire to a helicopter and a large number of vehicles inside the plant site, an officials said.
The rioters allegedly tried to attack expatriate workers in their camp inside the plant site but were pushed back by Yemeni troops who arrived with tanks and armored vehicles to contain the violence and restore calm.
The LNG plant, in the coastal city of Balhaf, is being constructed by Yemen LNG, which is partly owned by the Yemeni government and partly by France's Total energy company.
Yemen LNG confirmed the clashes took place in a press release, but did not report any injuries, only "undefined damage".
The company plans a full investigation of the incident, according to the release.