Lebanon's government has resigned amid mounting anger over the explosion on Tuesday that devastated parts of Beirut and left more than 200 people dead.
The announcement was made in a national TV address by Prime Minister Hassan Diab on Monday evening.
Many people have accused the country's leaders of culpability through their alleged negligence and corruption.
Protesters have taken to the streets and clashed with police for a third straight day.
The massive blast was caused by the detonation of 2,750 tonnes of ammonium nitrate stored unsafely at the port for years.
President Michel Aoun has asked the government to stay on in a caretaker capacity until a new cabinet is formed.
What did the prime minister say?
Mr Diab, who was appointed prime minister in January after months of deadlock, said his government had "gone to great lengths to lay out a road map to save the country".
But corruption in Lebanon was "bigger than the state" itself, and "a very thick and thorny wall separates us from change; a wall fortified by a class that is resorting to all dirty methods in order to resist and preserve its gains", he said.
"They knew that we pose a threat to them, and that the success of this government means a real change in this long-ruling class whose corruption has asphyxiated the country," he added.
"Today we follow the will of the people in their demand to hold accountable those responsible for the disaster that has been in hiding for seven years, and their desire for real change," Mr Diab said.
What happens next?
The prime minister presented himself in the speech as a reforming leader blocked by endemic corruption dating back years, BBC Middle East correspondent Tom Bateman says.
Parliament will now have to decide on a new prime minister – a process involving the same sectarian politics at the root of protesters' discontent, our correspondent adds.
It is unlikely to be a smooth or quick process due to the country's complex political system. Power in Lebanon is shared between leaders representing the country's different religious groups.
Additionally, following the end of the 1975-1990 civil war a number of warlords entered politics and still control large parts of the country's political, economic and social sectors.
Many protesters blame this entrenched system for the country's corruption.
On Monday police clashed with angry residents as protests continued in the capital following the government's resignation.
Footage showed protesters gathering near barriers leading to the parliament building as security forces fired tear gas at them.
How has Beirut been affected by the blast?
The death toll from last week's explosion has risen to 220 with 110 people still missing, Beirut city governor Marwan Abboud was quoted by the al-Marsad Online news website as saying.
Many foreign workers and lorry drivers were among the missing, he told Al Jadeed TV channel.
The huge blast damaged buildings in a radius of several kilometres in Beirut, leaving more than 200,000 people homeless or living in homes with no Read More – Source