People in Beirut have expressed anger at the government over what they say was negligence that led to Tuesday's huge explosion.
President Michel Aoun said the blast was caused by 2,750 tonnes of ammonium nitrate stored unsafely in a warehouse.
Many have accused the authorities of corruption, neglect and mismanagement.
The blast killed at least 137 people and injured about 5,000 others, while dozens are still missing. A two-week state of emergency has begun.
French architect Jean-Marc Bonfils, involved in rebuilding the city after the civil war, and firefighter Sahar Fares, one of the first responders at the scene, were among the first fatalities to be named. A German diplomat was also among the dead.
"Beirut is crying, Beirut is screaming, people are hysterical and people are tired," filmmaker Jude Chehab told the BBC, calling for the people responsible to face justice.
Chadia Elmeouchi Noun, a resident currently in hospital, said: "I've known all the time that we are led by incompetent people, incompetent government… But I tell you something – what they have done now is absolutely criminal."
On Wednesday, the government announced that a number of port officials were placed under house arrest pending an investigation into the explosion.
The country's Supreme Defence Council insisted that those found responsible would face the "maximum punishment".
Meanwhile, Amnesty International and Human Rights Watch have called for an independent investigation into the blast. In a statement, HRW said it had "serious concerns about the ability of the Lebanese judiciary to conduct a credible and transparent investigation on its own".
On Thursday President Emmanuel Macron became the first world leader to visit the country – a former colony of France – since the tragedy. He was mobbed as he walked around the city.
He told crowds he would not let aid go to "corrupt hands", and promised to call for a "new political pact" from the country's leaders.
Anger turns to fury
By Lina Sinjab, BBC News, Beirut
The country is still in shock. Almost every street in the city has been affected by some degree of damage.
The historical eastern neighbourhood of Gemmayze, known for its vibrant nightlife, is blanketed with broken glass. Windows, doors and in many places the rubble of historic buildings lay strewn around. It is simply beyond comprehension.
The Lebanese who took to the streets last October angry about their politicians are now furious and cannot believe how this could happen. The government says it has arrested several port officials, but for many this is not enough.
Every man in power should be held responsible, they say, and not only junior officials. Lebanese people have long been angry about the corruption and sectarian divisions among their politicians but now it is also about their own safety.
What triggered the explosion?
The ammonium nitrate – which is used as a fertiliser in agriculture and as an explosive – had reportedly been in a warehouse in the port for six years after it was unloaded from a ship impounded in 2013.
The head of the port and the head of the customs authority both told local media that they had written to the judiciary several times asking that the chemical be exported or sold on to ensure port safety.
Port General Manager Hassan Koraytem told OTV they had been aware that the material was dangerous when a court first ordered it stored in the warehouse, "but not to this degree".
House arrest would apply for all port officials "who have handled the affairs of storing [the] ammonium nitrate, guarding it and handling its paperwork" since June 2014, according to Information Minister Manal Abdel Samad.
The ammonium nitrate arrived on a Moldovan-flagged ship, the Rhosus, which entered Beirut port after suffering technical problems during its voyage from Georgia to Mozambique, according to Shiparrested.com, which deals with shipping-related legal cases.
The Rhosus was inspected, banned from leaving and was shortly afterwards abandoned by its owners, sparking several legal claims. Its cargo was stored in a port warehouse for safety reasons, the report said.
More on the explosion in Beirut
What is the latest on rescue efforts?
Security forces have sealed off a wide area around the blast site, and rescuers have been looking for bodies and survivors under rubble while boats search the waters off the coast. Dozens of people are still missing.
Public Health Minister Hamad Hassan said Lebanon's health sector was short of beds and lacked the equipment necessary to treat the injured and care for patients in critical condition.
Interactive See extent of damage at Beirut blast site
5 August 2020
25 January 2020
As many as 300,000 people have been left homeless by the blast, Beirut's governor Marwan Aboud said.
He told the BBC: "Beirut needs food, Beirut needs clothes, houses, materials to rebuild houses. Beirut needs a place for the refugees, for its people."
Economy Minister Raoul Nehme said the country would have to rely at least partly on foreign aid to rebuild.
"The capacity of the state is very limited, and so is that of the central bank and the banks. We're not swimming in dollaRead More – Source