It comes as visiting French President Emmanuel Macron warned that without serious reforms the country will “continue to sink”.
The blast on Tuesday, which appeared to have been caused by an accidental fire that ignited a warehouse full of ammonium nitrate at the city’s port, rippled across the Lebanese capital, killing at least 135 people, injuring more than 5,000 and causing widespread destruction.
It also may have accelerated the country’s coronavirus outbreak, as thousands flooded into hospitals in the wake of the blast.
Tens of thousands of people have also been forced to move in with relatives and friends after their homes were damaged, further raising the risks of exposure.
Mr Macron visited on Thursday amid widespread pledges of international aid.
But Lebanon, which was already mired in a severe economic crisis, faces a daunting challenge in rebuilding.
It is unclear how much support the international community will offer the notoriously corrupt and dysfunctional government.
Mr Macron, who viewed the devastated port and was to meet senior Lebanese officials, said the visit is “an opportunity to have a frank and challenging dialogue with the Lebanese political powers and institutions”.
He said France will work to co-ordinate aid but warned “if reforms are not made, Lebanon will continue to sink”.
Later, as he toured one of the hardest-hit neighborhoods, an angry crowd vented its fury at Lebanon’s political leaders, chanting “revolution” and “the people want to bring down the regime”, slogans used during mass protests last year.
Mr Macron said he was not there to endorse the regime and vowed French aid will not fall into the “hands of corruption”.
Losses from the blast are estimated to be between £7.6 billion to £11.4 billion, Beirut Governor Marwan Abboud told the Saudi-owned TV station Al-Hadath on Wednesday, adding nearly 300,000 people are homeless.
The head of Lebanon’s customs department meanwhile confirmed in an interview with LBC TV late Wednesday that officials had sent five or six letters over the years to the judiciary asking the ammonium nitrate be removed because of the dangers it posed.
But Badri Daher said all he could do was alert authorities to the presence of dangerous materials, saying even that was “extra work” for him and his predecessor.
He said the port authority was responsible for the material, while his job was to prevent smuggling and collect duties.
The judiciary and the port authority could not immediately be reached for comment.
The Government said on Wednesday that an investigation is under way and that port officials have been placed under house arrest.
The investigation into the explosion is focused on how 2,750 tons of ammonium nitrate, a highly explosive chemical used in fertilisers, came to be stored at the port facility for six years and why nothing was done about it.
The cargo had been stored at the port since it was confiscated from a ship years earlier.
Based on the timeline and the size of the cargo, that ship could be the MV Rhosus.
The ship was initially seized in Beirut in 2013 when it entered the port due to technical problems, according to lawyers involved in the case. It came from the nation of Georgia, and had been bound for Mozambique.
The stockpile is believed to have detonated after a fire broke out nearby in what appeared to be a warehouse holding fireworks.
Mr Daher said he did not know if there were fireworks near the ammonium nitrate.
Another theory is that the fire began when welders were trying to repair a broken gate and a hole in the wall of Hangar 12, where the explosive material was being stored.
Local news reports say the repair work was ordered by security forces who investigated the facility and were concerned about theft.
Security officials have declined to comment while the investigation is under way.
Port officials have rejected the theory in interviews with local media, saying the welders completed their work long before the fire broke out.
Dr Firas Abiad, director general of Rafik Hariri University Hospital, which is leading the coronavirus fight in the country, said he expects an increase in cases in the next 10 to 15 days linked to crowding at hospitals and blood donation centres after the blast.
The explosion was the most powerful blast ever seen in the city, which has survived decades of war and conflict.
Several city blocks were left littered with rubble, broken glass and damaged vehicles.
Authorities have cordoned off the port itself, where the blast left a huge crater and destroyed a large grain silo.
