Spain's government Tuesday rejected Catalonia's calls for self-determination after more than two million people took part in a symbolic vote on independence for the region.
Catalonia's leader Artur Mas reached out to Madrid for talks on a "definitive" and binding vote, but the national government, which had tried to ban Sunday's ballot, dug in its heels.
"The right to self-determination... is not possible, neither under our constitution nor in any of the other democracies around us," Deputy Prime Minister Soraya Saenz de Santamaria told parliament.
Demands for greater autonomy for the rich northeastern region have grown over recent years, fanned by Madrid's resistance and the recent economic crisis.
Catalonia accounts for a fifth of Spain's economy but also about six percent of its debts, according to official figures.
Mas said he had written to Prime Minister Mariano Rajoy on Tuesday inviting him "to set the conditions for a dialogue that is permanent and as constructive as possible".
The ultimate aim is to hold "a definitive and politically binding consultation" vote, Mas added.
Rajoy fiercely opposed Sunday's symbolic vote and has not reacted since the polls, in which 1.86 million people voted for independence.
Mas had hoped the vote would strengthen his hand in trying to force concessions from Rajoy, who has vowed to defend the unity of Spain as it recovers from recession.
But Madrid showed little sign of bending on Tuesday, with some members of the ruling Popular Party wanting to go after Mas in the courts.
"If what you want is independence for Catalonia, it will be difficult for us to come to an agreement," the deputy prime minister told the upper house Senate.
"Neither this party nor this government will vote for an agreement on secession."
The dispute looked set to drag on.
Mas did not rule out calling a snap regional election to be fought exclusively on the independence issue.
He said he would hold talks over the coming weeks with other Catalan political parties to gauge support for such a move.
State prosecutors are meanwhile taking their time investigating whether Catalan authorities breached court injunctions by opening polling stations in public buildings.
Mas's regional government said Monday that 2.3 million people took part in the vote, despite legal challenges and objections from the central government.
Anti-independence parties boycotted the referendum, saying the results would be skewed in favour of a break from Spain. It was organised by pro-independence volunteers.
There was no official electoral roll but the regional government said 5.4 million of Catalonia's 7.5 million residents were eligible to vote.
Recent polls have indicated that about half of Catalans favour independence overall.
Political analyst Jose Antonio Zarzalejos said Mas would likely hold a snap election by February, in order to leave enough time before municipal polls due in May.
"Madrid will not make any moves" in the meantime, Zarzalejos said.
Rajoy has one eye on the next general election, due a year from now.
"Mariano Rajoy will not give any ground, because his electorate would not forgive him," the analyst said.
"A solution will not come until the next legislature. In the current one, it is impossible."
Mas said on Tuesday that Catalan authorities suffered a massive cyberattack before and during the vote.
Hits on his government's computer systems multiplied 20,000 times on Saturday and 60,000 on Sunday in "hard, organised cybernetic attacks", Mas told reporters.
"We suspect that it could not just be a few amateur hackers or Twitter users who organised such a thing," he said. "We are examining another possibility."