Spanish Socialist leader Sánchez | Javier sorano/AFP via Getty Images Sánchez to Tsipras: I need a favor Spanish Socialist leader asks for Greek PM’s help getting Podemos to sign up to a coalition deal.

Spanish Socialist leader Pedro Sánchez called Alexis Tsipras on Thursday night to ask for the Greek leader's help convincing the far-left Podemos to join a coalition government.

Sánchez has made several attempts to get Podemos (We Can) leader Pablo Iglesias to sign up to his planned coalition, but Iglesias says he won't work with the centrist Ciudadanos (Citizens), with whom the Socialists have struck a coalition pact. If the Socialists can get Podemos on board, they would have enough seats to secure a majority in parliament.

The Socialist leader said he told Tsipras that Iglesias "should put himself on the side [of] those Spaniards who are suffering with the crisis, inequality and austerity policies that the Popular Party is putting into action."

He added that he wants Iglesias "to unlock the situation and allow us to have a government of change."

Sánchez and Iglesias have agreed to meet before Easter to discuss the differences between the two parties.

Tsipras and Iglesias have a good relationship. Last year, the Spaniard joined his fellow leftist on the Greek election campaign trail.

Time is running out for Sánchez to form a government and avoid fresh elections. Earlier this month, Podemos, the Popular Party of acting Prime Minister Mariano Rajoy and small leftist and regional parties all voted against Sánchez becoming prime minister during heated parliamentary sessions.

Speaking in Brussels Friday ahead of a second day of talks on an EU-Turkey migration deal, Rajoy said his party is still the best option for Spain.

"I still maintain that the proposal we made is the most reasonable and sensible and that generates more confidence," said the PP leader. "We are available to govern as the most voted party [in December's election], but without their [Socialists] abstention is not possible.

Talks will continue until May 2, but if no coalition deal is struck, parliament will be dissolved and new elections held on June 26.

This article was updated with quotes from Mariano Rajoy.