The northern section of the grain silos damaged two years ago by a blast at the Beirut port collapsed early on Tuesday after warnings the structure was leaning too far to stay up.
The crash sent a cloud of brown-grey dust billowing over the waterfront, the LBCI television station reported. There were no immediate reports of injuries.
The huge explosion at the port on August 4, 2020, killed more than 220 people and gutted the northern section of the grain silos, leaving wheat and corn spilling out in the sun.
Recently, a fire had been smouldering in the silos for weeks, which officials said was the result of summer heat igniting fermenting grain left rotting.
Part of the structure collapsed on July 31 and another section fell on August 4, the second anniversary of the blast.
On Sunday, the health ministry said dust samples from around the port showed that the air contained high amounts of common mould, which would not be dangerous unless inhaled in large quantities over a long period of time.
Israel and Iran attacked each other for a fifth straight day on Tuesday, and US President Donald Trump urged Iranians to evacuate Tehran, citing what he said was the country's rejection of a deal to curb nuclear weapons development.
Israeli tank shellfire killed at least 45 Palestinians as they awaited aid trucks in Khan Younis in the southern Gaza Strip, the territory's health ministry said, adding that dozens of others were wounded.
Russia launched hundreds of drones and dozens of missilesat Ukraine on Tuesday,hitting dozens of civilian targets in Kyiv including a large apartment block, killing at least 15 people and wounding scores, Ukrainian officials said.
US President Donald Trump left the Group of Seven summit in Canada a day early due to the situation in the Middle East, the White House said on Monday.
The U.S. military has moved a large number of refueling aircraft to Europe to provide options to President Donald Trump as Middle East tensions erupt into conflict between Iran and Israel, two U.S. officials told Reuters on Monday, speaking on condition of anonymity.
Sheikh Abdullah bin Zayed Al Nahyan, Deputy Prime Minister and Minister of Foreign Affairs, held phone calls with numerous counterparts from around the globe, as the Israel-Iran conflict entered its fifth day on Tuesday.