Prime Minister Mariano Rajoy's centre-right People's Party got the most votes in Spain's general election but not enough for a parliamentary majority, while leftist, anti-austerity, newcomer Podemos celebrated a surge into third place.

Podemos leaders and supporters gathered in Madrid to mark the unexpected shift which has tipped the balance to the left of the political spectrum.

Five left-wing parties led by the opposition Socialists and Podemos together picked up 175 seats, just one short of the number needed for a majority.

The fragmented vote heralds a new era of pact-making, shattering a two-party system that has dominated Spain since the 1970s and casting a pall over an economic reform programme that has helped pull the country out of recession.