'It's important that reforms be implemented' said UN chief Antonio Guterres on Lebanon

In a virtual meeting before Lebanon's prime minister announced the government's resignation on Monday, United Nations Secretary-General Antonio Guterres called for "a credible and transparent investigation determine the cause of the explosion and bring about the accountability demanded by the Lebanese people."

The Aug. 4 detonation at a port warehouse of more than 2,000 tons of ammonium nitrate killed at least 163 people, injured more than 6,000 and destroyed swathes of the Mediterranean capital, compounding months of political and economic meltdown. President Michel Aoun accepted the resignation and asked Prime Minister Hassan Diab's government - formed in January with the backing of Iran's powerful Hezbollah group and its allies - to stay as a caretaker until a new cabinet is formed, a televised announcement said.

Ahead of Diab's announcement, demonstrations broke out for a third day in central Beirut, with some protesters hurling rocks at security forces guarding an entrance leading to the parliament building, who responded with tear gas. Diab's government was under severe pressure to step down. Some ministers had already resigned over the weekend and Monday while others, including the finance minister, were set to follow suit, ministerial and political sources said.

Aoun has said explosive material was stored unsafely for years at the port. In later comments, he said the investigation would consider whether the cause was external interference as well as negligence or an accident.

Anti-government protests in the past two days have been the biggest since October, when angry demonstrations spread over an economic crisis rooted in pervasive graft, mismanagement and high-level unaccountability.