BEIRUT — In a massive show of force, Lebanon’s protestors loyal to Hezbollah and its political allies poured into the streets of downtown Beirut by the hundreds of thousands, dwarfing last weeks show of support for the government and delivering a sweeping rebuke to Lebanon’s political establishment.

The streets, squares and bridges of several neighborhoods were a sea of red and white Lebanese flags as supporters of the Shi’ite groups Hezbollah and Amal, as well as the Christian groups Marida and the Free Patriotic Movement, took to the streets in an attempt to topple the U.S.-backed government.

“The real problem with this government is that they did not stand with us during the war,” said Muhammad Obaid, 40, a Hezbollah supporter, echoing a common complaint of the opposition, which is also called the March 8 coalition.

Hezbollah, which is supported and armed by both Syria and Iran, captured two Israeli soldiers on July 12, prompting a massive retaliation by the Jewish state that turned into a 34-day war. More than 1,000 Lebanese died — mostly civilians — and the country’s infrastructure and industries were devastated. Hezbollah feels that the government in Beirut, which is led by Sunni politician Fuad Siniora, didn’t support it enough and even quietly hoped for it to lose the war so that the Shi’ite group would no longer be a viable political opponent.

Hezbollah emerged stronger than ever, however, and demanded more power in the government for itself and its allies in the March 8 coalition. After six cabinet ministers from their political bloc resigned, and Christian industry minister Pierre Gemayel was murdered, the March 8 forces hope to force the resignation of the Siniora government so that new elections can be held — which they feel they will win.

“The government will fall today,” Obaid said confidently.

Obaid comes from a small town in the Bekaa Valley east of Beirut, a stronghold for Hezbollah. He said that the group had paid him to drive his bus to ferry protestors to Beirut. From his village alone, he said there were four large buses and 15 minibuses.

By any count, the crowd was massive, easily topping 1 million people. It was unclear how many people were in the streets because of the sheer numbers, but today’s protest may have surpassed the original 2005 protest that gave Siniora’s bloc its name — the March 14 movement. That protest, coming exactly a month after the assassination of former premier Rafik Hariri, led to the end of Syria’s 29-year occupation of Lebanon, a defeat the regime in Damascus would like to undo with its allies in Lebanon, such as Hezbollah.

Packed and partying crowds of mostly young people stretched from the Christian neighborhood of Gemayze to the east, to the government buildings ringed by concertina wire on the other side of downtown toward the west, and from the site of Hariri’s grave near the port up to Sodeco Square in the Christian enclave of Achrafiye. They filled alleyways and overpasses, and all seemed to carry a flag of some sort.

Most carried the Lebanese flag, its red and white stripes framing a green cedar, but becoming a dramatic sweep when thousands upon thousands of the banners waved. But the Lebanese could not resist putting their own party’s stamp on their outfits, with Hezbollah members draping the milita’s flag about their shoulders and Michel Aoun’s Free Patriot Movement supporters wearing orange sweatshirts or baseball caps.

The crowd for the most part was friendly and respectful of the call by Hezbollah leader Hassan Nasrallah not to damage property or resort to violence, but a group of young toughs did celebrate the murder of Pierre Gemayel, by saying, “Congratulations to Pierre, when is Geagea next?” Samir Geagea is the leader of another Christian political party called the Lebanese Forces and is particularly hated by the Shi’ites of Lebanon. “We want your wife, Hakim,” they chanted referring to Geagea’s nickname and his wife, considered one of the more beautiful women in Lebanon. Their jibe was an ugly, sexist chant.

They called the interior minister a Jew while Hezbollah security stood by, watching impassively. It was only after I asked the youths why they were chanting such things — and their violent reaction when I said “I’m a reporter” in my badly accented Arabic — that the Hezbollah security guard intervened.

“They are not polite,” the guard said as he pushed me away roughly. “I don’t want you talking to people who aren’t polite.”

The March 8 movement has vowed to stay in the streets, staging sit-ins until the government resigns. As night fell, trucks carrying portable toilets and water tanks arrived while tents were being set up in Martyrs’ Square.

“If they don’t step down, we will stay here,” said Hayan Ismael, 22, a physics student from the Bekaa village of Bednayel and a supporter of another Christian group. He said protest organizers had timed the protests for Friday afternoon before the weekend to minimize the economic impact of shutting down the heart of Beirut, indicating that March 8 may be expecting a resolution by Monday morning. Downtown merchants have been complaining for months since the war about all the disruptions to business.

“Every day the government stays and doesn’t step down, it makes the economy suffer,” said Ismael.

Siniora, however, vowed last night not to step down.

“We will not allow a democratic government to be toppled or its institutions,” Siniora said in a televised address. “Nor will we allow a state within a state. We are the legitimate government and responsible for all Lebanese.”