All you need to know about Spain's big political parties and their leaders

Campaigning for Spain's national election kicks off on Friday. Following are snapshots of the main parties and leaders contesting the April 28 ballot.

SOCIALIST WORKERS' PARTY (PSOE)

Spain's oldest active party and one of two that have dominated the political landscape since General Francisco Franco's dictatorship ended in 1975. It has been in government longest since then.

Its leader Pedro Sanchez, 47 and a trained economist, has led a minority government since June when the Socialists unseated the conservative People's Party following a non-confidence motion. He called the election after parliament rejected his 2019 budget. In a bold move taken in June, he ordered the removal for re-burial of Franco's remains from a state mausoleum.

His government has raised the minimum wage by 22 per cent and tried to negotiate a greater degree of autonomy for Catalonia with its independence-minded government.

PEOPLE'S PARTY (PP)

A conservative, Christian democratic party, and the Socialists' main rival for decades. Pablo Casado, a 38-year-old lawyer and economist, became party leader a month after the government of his predecessor Mariano Rajoy was ousted. He is known as a defender of family values, the monarchy and the Catholic Church, and an opponent of abortion and euthanasia.

He has said he would slash taxes and famously called for Catalonia to be "reconquered" following the region's failed independence bid in 2017. As part of a wider investigation, a judge last year recommended the Supreme Court indict Casado for providing false information to get his Master's degree. But the court dropped the case, ruling that any irregularity committed did not amount to a crime.

CIUDADANOS (CITIZENS)

A centre-right, pro-European party originally from Catalonia and part of the Alliance of Liberals and Democrats for Europe. It made an electoral pact last year in the region of Andalusia that enabled the PP, backed also by Vox, to unseat the Socialist administration there. That earned Ciudadanos criticism for embracing populist nationalism. Its leader, Albert Rivera, 39, worked in a Barcelona bank before founding Ciudadanos in 2006. The party entered the Catalan parliament the same year after a campaign with a poster featuring a naked Rivera - with carefully obscured extremities - and the slogan: "Your party has been born, only you matter to us."

He strongly opposes making any concession to Catalan nationalists. The party first entered the 350-seat Spanish parliament in 2015, winning 48 seats.

UNIDAS PODEMOS (TOGETHER WE CAN)

An alliance of left-wing Podemos, United Left, Equo and other parties, created in the run-up to the 2016 national election and rooted in the anti-austerity protest movement. The name was regendered to make it female for the 2019 election to reflect its pro-feminism stance.

Its leader, a political scientist and lecturer Pablo Iglesias, 40, founded Podemos in 2014. In 2018 he denied receiving funding for his party from Venezuela and Iran, prompting counter-claims that the accusation was part of a smear campaign under Rajoy's government, which the PP has in turn denied.

VOX

An anti-immigration, nationalist party founded in 2013 by former PP members. It opposes gender equality laws and is strongly against autonomy for Spain's regions. Last year, it also became the first far-right party to win a seat in the Senate in four decades. Its leader Santiago Abascal, 42, is a tough-talking career politician from the Basque Country.

Echoing U.S. President Donald Trump's anti-immigration rhetoric, he has called for a secure wall to be built around the Spanish enclaves of Ceuta and Melilla and have neighbouring Morocco pay for it. "I am a supporter of discrimination," he told 7TV Andalucia in 2017.

(With inputs from agencies.)