MADRID (AP) — Socialist leader Pedro Sanchez will become Spain’s new prime minister after a no-confidence vote Friday in parliament unseated Mariano Rajoy’s conservative government. He came in vowing to address the “social emergencies” of the country’s citizens after years of austerity measures.

Sanchez, until now the head of Spain’s largest opposition party, could be sworn in by King Felipe VI as early as Saturday and will appoint his Cabinet over the coming days.

The 46-year-old takes the helm of the eurozone’s fourth-largest economy at a time when the European Union has to resolve numerous problems, including Britain’s impending departure from the bloc and political tensions over the tens of thousands of migrants who are still entering the continent from North Africa.

On the domestic front, Sanchez will head a minority government that will need to negotiate potentially difficult deals with other parties to get its legislation passed.

To prevent a power vacuum after a no-confidence motion, Spanish law makes the motion’s author — in this case, Sanchez — the country’s new leader as soon as the king swears him in.

The Madrid stock exchange was up 2 percent after Sanchez won the vote and earned a standing ovation from his party’s lawmakers.

Spain’s Prime Minister Mariano Rajoy, right, shakes hands with socialist leader Pedro Sanchez after a motion of no confidence vote at the Spanish parliament in Madrid, Friday, June 1, 2018. (Pierre Phillipe Marcou/Pool Photo via AP)

The end of Rajoy’s more than six-year reign as prime minister was the first ouster of a serving leader by parliament in Spain’s four decades of democracy.

It also was a rare success for a center-left party in Europe in recent times. Sanchez and his party are staunch supporters of the EU and the euro currency shared by 19 EU nations.

In a brief speech before the vote, Rajoy told lawmakers “it has been an honor to leave Spain better than I found it.”

He then shook hands with Sanchez after the result was announced.

Rajoy has been in power since December 2011, successfully steering Spain out of its worst economic crisis in decades during the eurozone debt crisis and achieving some of the strongest economic growth in Europe. Last year, gross domestic product growth reached 3.1 percent.

But the reputation of Rajoy’s Popular Party’s was badly damaged by a court verdict last week that identified it as a beneficiary of a large kickbacks-for-contracts scheme.

Sanchez saw that as his opening and managed to muster enough support from smaller parties to send him to La Moncloa palace, the seat of government in Madrid

Sanchez, who will be Spain’s seventh prime minister since the country’s return to democracy in the late 1970s, arrives in power after a spectacular turnaround in his political fortunes. He was ousted by his own party in 2016 over back-to-back losses in general elections and after he tried to block Rajoy’s bid to form a government.

The former economics professor and career politician regained the Socialists’ leadership last year.

The incoming prime minister says his priorities will be social issues — including more measures to help young people and the elderly. He told reporters Friday that he was “aware of the responsibility and the complex political moment of our country.”

He vowed to build consensus among political parties to “transform and modernize” Spain and “address the social urgencies of many people who suffer precariousness and inequality.”

He has promised to call a new election before the end of this term in 2020.

Still, Sanchez will face a tough time catering to demands from the small parties whose votes he captured in the no-confidence motion, among them Catalan separatists.

A new Catalan Cabinet is scheduled to regain the prosperous region’s self-government on Saturday, ending a seven-month takeover by central authorities in Madrid over the separatists bid to secede from Spain.

In a reversal from Rajoy’s aversion to Catalonia’s aspirations for greater autonomy, Sanchez has promised to open a dialogue with new Catalan President Quim Torra despite having called the fervent separatist’s comments “xenophobic.”

In other challenges, the center-right Ciudadanos (Citizens) party — which has been leading recent opinion polls — is demanding an early election and is vowing fierce opposition to Sanchez.