BARCELONA, Spain -- Secessionist parties who agree on breaking Catalonia away from Spain but little else started preparing Monday for tough political negotiations aimed at forming a regional coalition government to push their independence agenda despite a warning from Prime Minister Mariano Rajoy that any separation attempt won't be permitted.

The separatist "Together for Yes" pro-independence alliance on Sunday won 62 seats in Catalonia's 135-member parliament, six short of a majority, forcing it to seek support from the Popular Unity Candidacy anti-establishment separatist party that detests Artur Mas, the regional leader who called the vote.

No meetings were set Monday but both sides said talks would begin soon to form a regional government and pick its leader. The Popular Unity Candidacy party, known as CUP, won 10 seats and has lambasted Mas for invoking unpopular austerity measures.

Members said Monday they wouldn't support anyone to lead Catalonia's regional government linked to "cutbacks and corruption," a clear reference to Mas, who presided over cutbacks during Spain's years of economic hardship during the financial crisis.

While CUP leader David Fernandez promised his party will help the "Together for Yes" side because both share the common goal of independence, analysts predicted difficult negotiations. A new government isn't expected to be in place until November.

CUP is "in a tough spot: supporting Mas would antagonize its voter base, but forcing him to step down could paralyze the independence process," said Antonio Barroso, a London-based analyst with the Teneo Intelligence political risk consulting group.

Mas on Monday brushed off suggestions that his leadership was in question and insisted that under party agreements he has to be the regional presidential candidate.

He insisted the vote gave them a mandate to proceed with the independence drive and that they would work with CUP "to carry out the road map" and to put in place governmental structures needed for what he called "the legal disconnection" with Spain.

Prior to the elections, Mas and his group had pledged to work for an independent state within 18 months, including a unilateral declaration of independence.

But CUP's main candidate, Antonio Banos, said Monday that such a declaration couldn't now be justified as it would have needed the backing of more than half the votes.

Under the 41-year-old Fernandez, CUP has succeeded regionally in tapping into the same anger at austerity measures exploited by far-left European parties like Syriza in Greece.

Catalans, he said in an interview with The Associated Press last week, need to claim their sovereignty as a nation from a Spanish state he sees as having little respect for Catalonia and is an enthusiastic participant in a global capitalist economy he labels as "a war machine that robs, kills and lies."

Anti-secession parties played up the fact that the pro-independence parties won just 48 per cent of the popular vote.

That happened because of a quirk in Spanish voting law that gives votes from rural areas more value in selecting lawmaker seats than those from urban areas. And in Catalonia, there is more support for secession in less-populated areas.

Rajoy insisted that Spain won't be split apart and labeled the vote a failure because more than half of those who voted chose anti-independence parties.

"Those in favour of rupture never had the backing of the law and as of yesterday neither do they have the backing of the majority of Catalan society," he said.

The threat of Catalonia breaking away from Spain has been a constant source of bitter dispute between Mas and Rajoy's government, which rejects Catalan independence as unconstitutional.

Rajoy must call general election by the year's end with polls suggesting his party will lose its majority in the national parliament. His Popular Party took a beating in the Catalan elections, winning just 11 seats, eight fewer than in the previous legislature.

Mas has been Catalonia's regional president since 2010 and heads the Convergence party that has played a key role in Catalan politics for decades. Formerly opposed to independence, he started championing the cause in recent years the central government in Madrid government snubbed his effort to win more regional financial powers for Catalonia.

Throughout the campaign, Spain argued that independence would mean Catalonia being ejected from the European Union and out of the group of countries that use the euro.

The EU declined to comment Monday on the election outcome, saying it was an internal Spanish issue.

German Chancellor Angela Merkel's spokesman, Steffen Seibert, pointed to comments by Merkel a few weeks ago that the EU treaties guarantee the integrity and sovereignty of every country.

"So, from our point of view, it is important for the rule of law to be observed in all that happens now -- in relation both to the European treaties and national law," Seibert said. "The position of the German government is unchanged."

The newly elected Catalan deputies will take their seats by Oct. 27, with a new regional Catalonian government expected to be in place by early November.

Ciaran Giles reported from Madrid. Associated Press writer Geir Moulson contributed from Berlin