"The investigation of the incident will show whether it was a foreign intrusion or a Beirut's port personnel negligence," Aoun assured.
On Wednesday, authorities considered the 2,700 tonnes of ammonium nitrate, which were stored in a warehouse, were the possible detonator.
Multiple videos spread on social media suggest that a huge tremor-causing explosion was preceded by fire, possibly of firecrackers.
"We will look at how the explosive material entered the country and how it was stored. Then we will clarify whether the explosion was negligence or an accident. Finally, we will rule out the possibility that it was the consequence of outside intervention," Aoun said.
French rescue team departing paris orly airport for Beirut, Lebanon Today