BEIRUT -- Lebanon's prime minister gave his partners in government a 72-hour ultimatum to come up with "convincing" solutions for a rapidly worsening economic crisis, as nationwide protests against the country's entire ruling political class continued to escalate.

In an address to the nation and with hundreds of rowdy protesters camped outside his office, Saad Hariri blamed politicians in his national unity government, which includes the Iran-backed Hezbollah group and rival political parties, for blocking his reform agenda at every turn.

Following his speech, groups of rioters broke away from the protesters, clashing with police, setting cars ablaze and smashing store windows in the streets of Beirut.

Thousands of protesters have been rallying across the country for the past two days, raging against top leaders including the president, prime minister and parliament speaker whom they blame for decades of corruption and mismanagement that have led to the current crisis.

The protests are the largest Lebanon has seen since 2015 and could further destabilize a country whose economy is already on the verge of collapse and has one of the highest debt loads in the world.

The protests, triggered partly by a proposal for a $6 monthly fee for Whatsapp voicecalls, drew people from all religious and political backgrounds and were largely peaceful, although violence erupted in several areas. Many said they would remain on the streets until the government resigned.

Hariri said he understood the people's "pain" and anger at his government's performance and said "we are running out of time."

He said he was giving 72 hours for the government to come up with "clear, decisive and final" decisions regarding his proposed structural reforms to fix the ailing economy. Hariri appeared to suggest he would resign if that did not happen but stopped short of saying it.

Shortly after his speech, security forces fired tear gas and water cannons to disperse the protesters in central Beirut, leading to confrontations between police and young men in a downtown square. Others marched on the presidential palace in a southeast suburb of the capital.

The prime minister has led two national unity governments since 2016, which included his domestic rivals Hezbollah. The current government is dominated by the group and its allies.

The militant group has remained silent about the protests.

Time and again, the protesters shouted "Revolution!" and "The people want to bring down the regime," echoing a refrain chanted by demonstrators during Arab Spring uprisings that swept the region in 2011.

They took aim at every single political leader in the country, including President Michel Aoun and his son in law, Foreign Minister Gebran Bassil, as well as the prime minister and parliament speaker, blaming them for systemic corruption they say has pillaged the country's resources for decades.

"We are here today to ask for our rights. The country is corrupt, the garbage is all over the streets and we are fed up with all this," said Loris Obeid, a protester in downtown Beirut.

Schools, banks and businesses shut down as the protests escalated and widened in scope to reach almost every city and province. Hundreds of people burned tires on highways and intersections in suburbs of the capital, Beirut, and in northern and southern cities, sending up clouds of black smoke in scattered protests.

The road to Beirut's international airport was blocked by protesters, stranding passengers who in some cases were seen dragging suitcases on foot to reach the airport. Major arteries including the Salim Salam tunnel that connects central Beirut with the airport were blocked with sand dunes.

"We are here for the future of our kids. There's no future for us, no jobs at all and this is not acceptable any more. We have shut up for a long time and now it is time to talk," Obeid added.

In the northern city of Tripoli, bodyguards for a former member of parliament opened fire at protesters who closed the road for his convoy wounding three of them, witnesses said.

The tension has been building for months, as the government searched for new ways to levy taxes to manage the country's economic crisis and soaring debt.

The trigger, in the end, was the news Thursday that the government was planning, among other measures, to impose a tax on Whatsapp calls -- a decision it later withdrew as people began taking to the streets.

Two Syrian workers died Thursday when they were trapped in a shop that was set on fire by rioters. Dozens of people on both sides were injured.

Years of regional turmoil -- worsened by an influx of 1.5 million Syrian refugees since 2011 -- are catching up with Lebanon. The small Arab country on the Mediterranean has the third-highest debt level in the world, currently standing at about $86 billion, or 150% of its gross domestic product.

International donors have been demanding that Lebanon implement economic changes in order to get loans and grants pledged at the CEDRE economic conference in Paris in April 2018. International donors pledged $11 billion for Lebanon but they sought to ensure the money is well spent in the corruption-plagued country.

Despite tens of billions of dollars spent since the 15-year civil war ended in 1990, Lebanon still has crumbling infrastructure including daily electricity cuts, trash piles in the streets and often sporadic, limited water supplies from the state-owned water company.

------

Associated Press writers Fadi Tawil, Hassan Ammar and Bassam Hatoum in Beirut contributed reporting