Aoun said on Friday an investigation would examine whether the blast was caused by a bomb or other external interference.
He said the investigation would also weigh if it was due to negligence or an accident. Twenty people had been detained so far, he added.
'We can't afford to rebuild'
Officials have said the blast could have caused losses amounting to $15 billion. That is a bill that Lebanon cannot pay after already defaulting on a mountain of debt — exceeding 150 percent of economic output — and with talks stalled on an IMF lifeline.
For ordinary Lebanese, the scale of destruction is overwhelming. Marita Abou Jawda was handing out bread and cheese to victims of the blast.
"Macron offered to help and our government has not done anything. It has always been like that," she said. "After Macron visited I played the French national anthem all day in my car."
(Writer: Michael Georgy | Editors: Frances Kerry, Nick Macfie)
Dapatkan update berita pilihan dan breaking news setiap hari dari Kompas.com. Mari bergabung di Grup Telegram "Kompas.com News Update", caranya klik link https://t.me/kompascomupdate, kemudian join. Anda harus install aplikasi Telegram terlebih dulu di ponsel.