Tens of thousands of demonstrators demanded the resignation of Lebanon’s embattled government on Saturday, clashing with police and soldiers and railing at a political class they universally blamed for the catastrophic explosion that destroyed parts of Beirut last Tuesday. The rally in the capital’s Martyrs’ Square was preceded by the resignation of three MPs from the nearby Lebanese parliament. The seething crowd called for others to follow, and Hassan Diab, the Lebanon prime minister, called for early elections, potentially after two months. Earlier, the reaction of besieged leaders had been to license a hardline response from security forces, who barraged parts of the rally with teargas and fired into the air when rock-throwing protesters neared the parliamentary precinct. By 9pm, relentless barrages of teargas had cleared the square, but the energy and foreign ministries had been infiltrated by protesters and the environment ministry was torched. Anger had built throughout the afternoon in the shadow of what remained of the Beirut port. Crowds poured into the square – the scene of ebullient anti-government protests last October – throughout a steamy afternoon. Large numbers walked from areas which had been severely damaged by the explosion that killed at least 157 people and wounded close to 5,000 others. Many of the demonstrators had rallied in the weeks after the 17 October uprising, which led to the resignation of the then government and the installation of some new faces who answered to the same leaders. “We just can’t do this any more,” said Julie Warde, 24, a physiotherapist from Zahle. “As someone who works in the medical sector, I’ve seen how the crisis since October has affected everything, how no one can afford anything. This is the end.” A friend, Jean Helou, 24, said: “We have a criminal president and we want to kill him. I was here in October and we were angry then. Nothing has changed. What did they expect us to do after this?” The lack of reform had been a constant refrain before the port explosion, caused by nearly 3,000 tons of ammonium nitrate detonating after a fire. The cataclysmic damage is considered to be one of the world’s biggest ever industrial accidents. Yusuf Shehadi, a former port worker told the Guardian on Saturday that in 2010 he had been asked to store 30 to 40 large bags of fireworks in the same hangar in which the nitrate was later moved in 2014. The sheer scale of negligence and widespread carnage it caused has galvanised an angrier response than in any anti-government rally in recent years. “I swear that anyone who dies protesting this is a martyr,” said Issa Beddawi, as he walked to the square. Rachel Raedi, 20, came to the protest carrying a placard with a picture of her friend Rawan Msto, who died from blast injuries in an intensive care unit on Friday. Underneath Msto’s smiling face was the bleak message: “My government killed me.” “We were here in October, so was our friend. She was campaigning for change to make Lebanon a better place. Now she is dead,” Raedi said. Families who arrived at the rally with children quickly left as dozens of teargas canisters were fired. “It was very different,” said Ghassan Haddad, as he walked into a nearby neighbourhood. “It wasn’t like October.” A mock noose and a hangman’s scaffold were hung in the square, along with cardboard cutouts of leaders. One man tore down a photo of Hezbollah leader, Hassan Nasrallah. Another smashed an image of president Michel Aoun. In the midst of the rally, the mother of a port worker who died screamed: “Justice, we need justice. I don’t care if I die here today. They will stop us marching over my dead body.” Earlier, the head of the Lebanese Forces bloc, Sami Gemayel, announced his resignation from parliament by addressing the country’s implacable old guard. “A new Lebanon must be born on the ruins of the old one, which you represent.” Another MP, Paula Yacoubian, said she could no longer bear ‘“false witness” to the parliament. Five MPs from the 128-seat legislature have now resigned. A total of 43 would have to quit for the government to fall. As evening closed in, the sound of gunfire intensified as soldiers repeatedly shot in the air. So did the wail of sirens, a cacophony of which were a soundtrack to Tuesday’s devastation, and continued into the early hours of Wednesday. Lebanese leaders maintained a silence on Saturday. None had visited the scenes of the explosions, and two ministers who attempted to do so on Friday were chased away. One Lebanese broadcaster, LBC, said it will no longer broadcast political speeches or updates from leaders on the investigation, which has so far placed up to 15 port bureaucrats under house arrest. An international probe into the cause of the explosion and the circumstances that led to such a lethal stockpile being stored near central Beirut for six years was a central demand of protesters. Elsewhere, prominent Lebanese figures stressed an urgent need for new governance. “The next step is a salvation government [from outside the political class] with a special mandate to address the humanitarian and economic crisis,” said Nadim Khoury, executive director of the Arab Reform Initiative. It should have a limited mandate of two to three years, and its duty would be to prepare for elections on the basis of a new electoral law. “The current political class won’t accept this obviously. This is why what is needed is maximum resignations and a popular effort to remove the ‘legitimacy’ from the current order until they realise they cannot govern anymore because no one is listening,” he said. Demanding the government resign, the director of the Carnegie Middle East Centre, Maha Yahya, said: “The political parties are invested in the status quo because for the longest time state institutions were their golden goose. Now that goose is dead and the state is bankrupt. But they have no other way to continue offering favours to their constituents.” Lebanon’s leaders have been warned by the French president, Emmanuel Macron, and the IMF that an influx of humanitarian aid does not mean the end of a reluctance to bail out the country from a crippling economic crisis. “That’s the only good news I’ve heard this dreadful week,” said Elias Abouzeid. “May God damn these thieves.”