By David Latona and Belén Carreño
MADRID (Reuters) - Acting Spanish Prime Minister Pedro Sanchez anticipated "complex talks" with other political parties after he was nominated on Tuesday to seek support in a parliamentary vote for a new mandate.
Sanchez said he would work on securing backing not only to form a government but also to pass legislation as a minority coalition for the rest of his four-year term.
The Socialist leader is seeking a second four-year term and will need to win an investiture vote with the support of potential coalition partners, the hard-left Sumar, as well as several Catalan and Basque nationalist parties, some of which advocate independence for their regions.
If no candidate secures a majority by Nov. 27, a repeat election has to be called.
"I've accepted the task given to me by the head of state... I am willing to work to form as soon as possible a progressive coalition government with enough support to guarantee the stability that the country needs," Sanchez told reporters.
In an inconclusive general election on July 23, Sanchez's Socialists secured fewer seats than the conservatives of Alberto Nunez Feijoo.
He was invited by King Felipe VI to try to form a majority after Feijoo failed in his bid to become premier last week.
Sanchez believes he can muster enough backing for his candidacy which would include Catalan separatist parties Junts and Esquerra Republicana de Catalunya.
The two parties are demanding a controversial and unpopular amnesty in exchange for their votes in parliament.
While avoiding explicitly mentioning an amnesty during a press conference in Madrid, Sanchez defended as a success his 2021 decision last year to pardon Catalan leaders jailed over a failed independence bid in 2017.
Sanchez said the crisis - which prompted the conservative government at the time to temporarily impose direct rule from Madrid - "brought nothing good".
"It was a crisis of which no one can feel proud - I wasn't leading the government then," he said. "Since then I have tried to overcome that situation."
He argued that political conflicts need to be resolved "in the political field and not elsewhere", and now was the time for "politics, generosity and leadership".
"If July 23 told us anything about Spaniards, it's that you cannot lead the government of this nation without understanding the plurality of parliament and the diversity of the country."
Sanchez said he would like to complete the talks and set a date for a vote "as soon as possible".
House Speaker Francina Armengol said earlier that Sanchez had yet to share with her his suggested schedule for the investiture vote.
He said he would start talks with the main parties on Wednesday, beginning with his Labour Minister Yolanda Diaz, the head of Sumar.
"What I can promise you is that I am going to put my heart and soul into a negotiation that is not going to be an easy one," he said.
(Reporting by David Latona, Belen Carreno Emma Pinedo and Inti Landauro; Writing by Charlie Devereux; Editing by Andrei Khalip and Nick Macfie)