Hundreds of protesters blocked major highways in Lebanon Friday Riot police were deployed in the centre of Beirut Friday evening BEIRUT: Thousands of protesters outraged by corruption and proposed tax hikes burned tyres and blocked major highways in Lebanon on Friday, prompting the premier to give his government partners three days to support a reform drive. Demonstrations flared Thursday, partly sparked by a proposed tax on calls via messaging apps such as WhatsApp, and grew into the largest in recent years, threatening to topple Prime Minister Saad Hariri"s fragile coalition government. After his speech, clashes flared in central Beirut"s Riyadh al-Solh Square between demonstrators and security personnel, who fired volleys of tear gas to clear the plaza. Thousands of people of all ages, sects and political affiliations ha d brought the capital to a standstill Friday, with demonstrations reported across the country. The protesters are demanding a sweeping overhaul of Lebanon"s political system, citing grievances ranging from austerity measures to poor infrastructure. In a televised address Friday evening, Hariri said he understood their anger and was trying to push through change. He called on his coalition partners to give a "clear, decisive and final response to convince me, the Lebanese people and the international community... that everyone has decided on reforms, or I will have something else to say." He gave them a 72-hour deadline to do so, without directly threatening to resign. Foreign Minister Gebran Bassil earlier warned the government"s resignation could lead to "something much worse". Many protesters had been expecting Hariri to announce his resignation. Protestor Carol dismissed the three-day deadline, saying "they had 20-30 years to fix stuff". best thing would be for them to step down," the 27-year-old said. Riot police were deployed in the centre of Beirut Friday evening, readying for a second night of protests and rioting, an AFP correspondent said. Ensuing clashes wounded at least 17 riot police officers, the Internal Security Forces said on Twitter, adding to 60 injured the previous day. The number of wounded protesters was not yet clear as of Friday night. READ MORE: Saudi Arabia, other Middle East countries warn citizens after protests erupt in Lebanon Lebanon, which in 1990 emerged devastated from a 15-year civil war, maintains a complicated political system balancing the influence of Christians, Sunni and Shia Muslims and other religious groups. The current government has backing from across the political spectrum but faces financial woes including a ballooning deficit. Public anger surged after parliament passed an austerity budget in July, and on Thursday it flowed into the streets over plans to introduce a $0.20 tax on calls via messaging apps, widely used in Lebanon. The government scrapped the proposal within hours, but demonstrations carried on into the night. Security forces finally dispersed them shortly before dawn, firing volleys of tear gas and rubber bullets after attempts to storm government headquarters. So far at least 23 protesters have been injured, according to the Red Cross. Banks, state institutions, schools and universities were closed Friday as the rallies spread throughout the country. Reflecting the scale of public anger, rare demonstrations were reported in neighbourhoods dominated by powerful Shiite movement Hezbollah, not used to opposition in its own bastions. South of Beirut, travellers trying to reach the airport had to leave their luggage behind, hitching rides on scooters and clambering over roadblocks. Protesters in various locations burnt or trampled posters of Hariri, Speaker Nabih Berri and President Michel Aoun. Sami Nader, director of the Levant Institute for Strategic Affairs, said the protests were "totally spontaneous" and appeared to target the entire political class. "The protests are a result of a piling up of grievances, resulting mainly from government mismanagement," he said. They are the largest demonstrations since a 2015 refuse collection crisis sparked widespread anti-government protests. Lebanon suffers from constant electricity shortages and poor internet. "I want the streets to be lit. I don"t want to hear any more generators," said Dima Abu Hassan, 42. "Start there -- at least some infrastructure." The government has also faced heavy criticism over its response to forest fires earlier this month. In a country with one of the world"s highest debt burdens, the government is weighing a raft of belt-tightening measures aimed at shoring up finances and securing $11 billion in aid pledged by international donors last year. It is expected to announce a series of new taxes as part of next year"s budget, currently being drawn up by ministers. Growth has plummeted in recent years, with political deadlock, compounded by the impact of eight years of war in neighbouring Syria. On Thursday the International Monetary Fund forecast "a continuation of weak growth in 2019". Lebanon"s public debt stands at around $86 billion -- more than 150 percent of gross domestic product -- according to the finance ministry.