MADRID (Reuters) - Spain’s Socialists increased their lead in two polls published late Saturday, with support from 28.8% to 30.3% of voters, but they fell short of a majority ahead of a general election on April 28.

FILE PHOTO - A worker places an electoral poster of Spain's Socialist leader and current Prime Minister Pedro Sanchez in La Fresneda, Spain April 12, 2019. REUTERS/Eloy Alonso

A poll by El Pais newspaper gave the Socialists of Prime Minister Pedro Sanchez 129 out of 350 seats in the parliament. If a coalition was formed with their main ally, anti-austerity Podemos, they would hold a combined 162 seats, short of the 176 needed to secure a majority.

A coalition of three right-wing parties - People’s Party (PP), Ciudadanos and Vox - would get 44.4% of votes, or 156 seats, 20 short of a majority.

To be reelected, Sanchez would have to form a wide-ranging and delicate parliamentary majority with the support of the array of parties, including Podemos and Catalan pro-independence parties, that backed him last June when he won a vote of confidence against PP’s government at the time.

But last February those Catalan parties voted against his budget proposal, forcing him to call for a snap election.

Another poll published by newspaper El Mundo gave the Socialists a potentially closer path to the premiership, but also to the three right-wing parties, in a sign of how close next week’s election could be.

A coalition of PP, Ciudadanos and Vox would have 152 to 174 seats. The latter figure would be only two seats short of a majority.

The Socialists and Podemos would have the same number of seats as the right-wing parties with an estimated total of 152 to 174 seats.

But Sanchez could be reelected as prime minister if, beyond Podemos, he manages to get the support of one or a few small regional parties, allowing him not to rely on Catalan pro-independence groups.

Both polls also show that the Socialists could get a majority if they reached a parliamentary alliance with Ciudadanos, as they did in 2016, but the center-right party has clearly ruled out that possibility.

The polls show some diverging estimates. El Mundo sees PP obtaining 20.1% of votes, gaining one percentage point since a February 24 poll. While El Pais projects that its support would decrease from 19.3% in a poll on March 24 to 17.8%.

In the case of Vox, in El Pais poll, its backing increases from 10.2% of votes a month ago to 12.5%. But in El Mundo it loses ground, from 13.3% to 10.2%.