By Sarah White
MADRID (Reuters) - Spain's left-wing political parties intensified negotiations on Monday to end weeks of wrangling after an inconclusive election, though leaders had yet to make any breakthrough on forming a coalition to avoid another ballot.
Spain's Socialist Party, runner-up in the election, is racing to try and strike a deal with rival parties. Leader Pedro Sanchez faces a confidence vote in parliament on March 3 on his plan for a government.
The Dec. 20 poll left Spanish political parties far short of a majority in the 350-seat lower house. The center-right People's Party (PP) won the most votes but said it lacked support to try and form a government first.
The first four-way meeting on Monday between the Socialists' negotiating team, anti-austerity Podemos and two smaller leftist forces, raised expectations that talks were finally progressing.
"We agree on priorities, it's been a good start, we're yet to make it concrete," senior Podemos member Inigo Errejon told a news conference, after nearly five hours. Talks are set to resume on Tuesday evening.
Socialist officials noted that the four leftist parties did not have enough seats between them to clinch a majority in parliament.
"We've agreed on the agenda" for negotiations, Socialist parliamentary spokesman Antonio Hernando said. "We did not get into the big themes."
Socialist Sanchez also met separately with his counterpart from centrist party Ciudadanos on Monday afternoon, exploring alternatives to a leftist pact.
Podemos and Ciudadanos, two new forces that previously had no seats in the national parliament, grabbed millions of votes from the PP and the Socialists after a deep economic crisis.
To reach a potential leftist pact, the Socialists and Podemos must overcome differences over issues such as an independence referendum in the Catalonia region.
Any alliance between the Socialists and Ciudadanos would still need the unlikely backing of Podemos or the PP to work, if they manage to reach an agreement.
"We're as close to a deal with the Socialists as we are to getting up from the table," Ciudadanos leader Albert Rivera told Cadena Ser radio earlier on Monday.
Fresh elections could take place in late June if Sanchez fails in his bid to form a government and rivals including the PP struggle to present a viable alternative.
A Sigma Dos opinion poll published on Sunday in El Mundo newspaper showed the PP, battered in recent weeks by news of corruption scandals, would lose four seats in the parliament compared to the December ballot. Podemos would lose nine. Ciudadanos would gain the most.
New elections would do little to resolve the deadlock.
Another Sigma Dos poll on Monday showed 48 percent of the PP's voters did not back their party's Mariano Rajoy, currently the acting Prime Minister, to run again as leader in a repeat election.
Rajoy insisted in a television interview that he would stand again, reiterating his preference for a "grand coalition" between the Socialists, the PP and Ciudadanos.
"If Mr Sanchez doesn't manage to get elected (in the confidence vote), or he'll have to say he can get on with the PP, or there will be fresh elections," Rajoy told 13TV.
(Reporting by Blanca Rodriguez and Sarah White; Editing by David Gregorio)