BEIRUT -At least 28 people were killed and 79 injured when a fuel tank exploded in northern Lebanon early on Sunday, the health ministry said.
Military and security sources said that the army had seized a fuel storage tank hidden by black marketeers and was handing out gasoline to residents when the explosion occurred.
Lebanon is suffering from a severe fuel shortage, leading to long lines at gas stations and extended blackouts.
Accounts varied as to what caused the explosion, from gunfire that hit a tank of gasoline to reports that it was caused by a person who ignited a lighter.
Protesters, already angry at the economic crisis in the country, put the blame squarely on Lebanon's politicians as they demonstrated outside the prime minister's residency and hurled rocks at the building.
"Akkar was put on fire by its deputies in parliament," protesters sprayed on the building, referring to one of Lebanon's poorest areas, where the explosion occurred.
Abdelrahman, whose face and body was covered in gauze as he laid in Tripoli's al-Salam hospital, was one of those in line to get gasoline.
"There were hundreds gathered there, right next to the tank, and God only knows what happened to them," he said.
Witnesses said about 200 people were nearby at the time of the explosion. Army and security forces personnel were among the casualties, sources said.
President Michel Aoun wrote on Twitter that "this tragedy that befell our dear Akkar has made the hearts of all Lebanese bleed".
He said he had asked the judiciary to investigate the circumstances that led to the explosion.
Security forces fired tear gas to disperse the dozens of protesters outside the residency of Prime Minister designate Najib Mikati, witnesses said.
"Although I understand the cries of people and their right to protest, what happened... is not a peaceful protest but unacceptable vandalism," Mikati said in a statement.
With Lebanon deep in economic crisis, hospitals have warned that fuel shortages may force them to shut down in coming days, and have also reported low supplies of medicines and other essentials.
"The Akkar massacre is no different from the port massacre," said former Prime Minister Saad al-Hariri on Twitter, referring to last year's massive explosion at the port in Beirut.
He called on Lebanese officials including the president to take responsibility and resign.