Several ministers had already stepped down from their posts in the aftermath of the devastating blast.
Diab attributed the August 4 blast, which killed at least 163 and wounded nearly 6,000, to endemic corruption.
“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,” he said in a speech this evening.
Many blame government dysfunction for the disaster, which reinvigorated the Lebanese people’s calls to end debilitating corruption.
Over 2,000 tons of highly explosive ammonium nitrate were stored for six years without proper supervision at the Beirut port.
Following months of mounting unrest and protests due to poor governance and economic crisis, the country’s troubles came to a head with the explosion.
Protestors stormed ministries over the weekend, which saw violent clashes between demonstrators and security services.
Several ministers stepped down as protests raged on, prior to the prime minister’s announcement.
After one-third of his cabinet resigned, Diab himself was forced to announce he would yield his post.
Diab had announced on Saturday his intention to urge early elections. On Sunday, Lebanon’s ministers of information and environment resigned.
Minister of Justice Marie-Claude Najm resigned on Monday. Reports suggest Finance Minister Ghazi Wazni was also preparing his resignation.
Lebanon’s current cabinet assumed their positions in January with the country already embroiled in crisis.
Following last week’s disaster, many Lebanese are insisting on a larger government overhaul. The resignation of cabinet members will not suffice given the severe shortcomings of Lebanon’s government, evident in the negligence that led to the blast, anti-government protestors say.
The explosion displaced at least 300,000 people, and Beirut residents are living in homes with shattered doors and windows.
The city’s infrastructure also took a hard hit, with two main water and electricity stations sustaining significant damage.
Although 163 deaths have been reported, Beirut governor Marwan Abboud said the death toll has reached 220, with 110 still missing, according to al-Marsad.
Lebanon’s cabinet declared a two-week state of emergency on August 5.