BEIRUT -- Lebanon's president tasked former Prime Minister Saad Hariri with forming a new government Thursday, bringing back the veteran politician a year after he was toppled amid nationwide protests against widespread corruption and a flunking economy.

President Michel Aoun designated Hariri after a slight majority vote by lawmakers, securing the return of an old name to lead the country desperate for change.

Hariri now faces a more impoverished Lebanon, devastated by a massive August explosion that defaced Beirut, but also a more determined opposition.

The 50-year-old politician takes the helm with a sense of urgency and more involvement by international leaders who have warned Lebanon is on the verge of collapse. Hariri pledged to quickly form a new government - his fourth in the last decade - to halt the economic collapse, calling it the “last and only” opportunity.

The task is enormous, amid an unprecedented economic crisis and stiff opposition, including from former political allies and protesters demanding change. “Saad, don't dream of it,” read posters raised by protesters, who see him as a symbol of an entrenched political class they blame for the country's woes.

In the past year, Lebanon's currency has collapsed, losing nearly 80% of its value while prices, unemployment and inflation soared. Lebanese have been unable to access their savings, as banks imposed informal capital controls, fearing a run on deposits.

The gigantic August explosion in Beirut's port, caused by thousands of tons of highly explosive chemicals stored in a warehouse, compounded the crises. The blast, which killed nearly 200 people and injured over 6,000, was seen as further proof of an incompetent political class that has governed the small country since the end of its 15-year civil war in 1990.

“As if nothing happened at all this whole year. Hariri is back and the (political class) is pleased,” said Hayat Nazer, a protester and artist. “It is clear they have ignored the public's outcry.”

Hariri vowed to stop the economic, social and security meltdown and rebuild after the port explosion: “I say to Lebanese who are suffering hardship to the point of despair, I am determined to keep my promise.”

Human Rights Watch said Lebanon's domestic probe into the blast has been marred by political meddling and lack of judicial independence. The group called Thursday for a UN-led inquiry to determine responsibility.

Hariri's successor last year - a university professor who led a government supported by Hezbollah and its allies - stepped down after the Aug. 4 blast.

The explosion prompted France, a longtime ally and former colonial ruler, to push for a new political order in Lebanon. Paris launched what came to be known as the French initiative, designed to pressure rival politicians to agree on a government empowered to introduce wide-ranging economic reforms. The international community has said it will not help Lebanon financially before reforms are implemented.

Hariri pledged a government of non-partisan specialists tasked with implementing reforms according to the French initiative, endorsed by mainstream Lebanese politicians. Its priority is to resume talks with the IMF for a desperately needed bailout, amid rapidly shrinking foreign currency reserves.

But Lebanon's complex sectarian-based political system makes reaching major decisions a significant challenge. Power, including government posts, is distributed among the country's Shiites, Sunnis and Christians who often get bogged down in horse trading because of fears of losing their calibrated clout.

The French initiative first resulted in the naming of Mustapha Adib, a technocrat backed by Hariri, as prime minister-designate. But Adib stepped down a month later, after failing to form a government of specialists because Shiite political groups insisted on naming the sect's ministers.

Hariri has since re-emerged as the only contender. The son of assassinated former Prime Minister Rafik Hariri, he took over his slain father's mantle in 2005 and enjoys good relations with the West. He secured 65 votes out of 120 lawmakers polled on Thursday by Aoun amid sharp divisions over the shape of the future Cabinet.

With Saad Hariri, as leader of Lebanon's largest Sunni political party, at the helm, rivals have argued his Cabinet should include a mix of experts and politicians. A former ally, the Free Patriotic Movement, Aoun's party and the largest largest Christian party, withheld support to Hariri. Another major Christian party and former ally of Hariri also withheld support.

The powerful Shiite militant group Hezbollah supports Hariri's designation but refrained from voting for him to avoid appearing to be breaking ranks with its ally, Aoun's party. Hariri got backing from the other Shiite group, Amal, as well as a small Christian party and independents.

Gebran Bassil, the head of Aoun's party, said his bloc expected Hariri to form a government that represents political parties, even if it included technocrats.

In a speech on the eve of the consultations, Aoun signalled he would not stop Hariri from being named prime minister but indicated he wants a bigger role in government formation. Most observers expect a rocky process.

“Today, I am required to designate (a prime minister) and then participate in the formation of a government,” Aoun said. “Will the one who is nominated commit to addressing corruption and launching reform?”

Portending tensions ahead, protesters who took to the streets Wednesday rejecting Hariri's nomination were heckled by his supporters amid heavy security deployment. Hariri's supporters also set fire to a large depiction of a fist that symbolizes the uprising against the old political class. A new fist was raised on Thursday.