Beirut, Sep 11 : A major fire that broke out at the Port of Beirut, which came more than a month after the facility was hit by two massive explosions, might have been caused by an intentional act of sabotage, a technical error, ignorance or negligence, said President Michel Aoun. "In all cases, we must investigate the reasons behind this fire and hold perpetrators accountable as soon as possible," Xinhua news agency quoted Aoun as saying at a meeting on Thursday just hours after the blaze was reported. Aoun stressed that work must currently focus on studying effective measures to ensure that such incidents do not repeat in the future. The cause of the fire, which broke out in a warehouse where an aid agency had been storing food and cooking oil, is yet to be determined. But preliminary information revealed that welding work in the warehouse caused the fire. Firefighters and military officials spent hours battling the fire, using helicopters to drop water on it, before getting it under control on Thursday night. No injuries were reported. The fire broke out just over a month after the August 4 explosions in the port that claimed the lives of 190 people, injured thousands others and left as many as 300,000homeless. The explosions were caused by 2,750 tonnes of ammonium nitrate detonating at a warehouse in the port. /IANS