Lebanon’s Interior Minister, Mohammed Fahmi, says the Tuesday explosion in Beirut was caused by ammonium nitrate.
He said the chemical was stored in a warehouse at the port.
More than 50 people were feared dead, with nearly 3,000 injured.
Prime Minister, Hassan Diab, disclosed that the warehouse had been the subject of warnings since 2014.
Diab assured that he would “reveal facts” about the facility soon.
“I promise you this catastrophe will not pass without accountability. The people who are responsible will pay a price,” Diab said.
The PM declared Wednesday a national day of mourning for the victims of the explosion.
Israel, technically at war with Lebanon and being accused of complicity, has also offered humanitarian assistance.
Defence Minister, Benny Gantz, said Israel approached the Lebanese government through “international security and diplomatic channels”.
Similarly, Canada, France, the United Kingdom, the United States and other countries have offered assistance.