Video report by ITV News Correspondent Emma Murphy
With more than 50% of votes counted in the Catalan election, the regional electoral board said pro-independence parties are set to regain their majority.
Polls opened across Catalonia on Thursday in a pivotal regional election the Spanish government hopes will end a political deadlock sparked by the region's deeply polarising independence bid.
As early results came in, the party of ousted Catalan leader Carles Puigdemont - currently in exile in Brussels - claimed victory for the separatist bloc.
Agusti Alcoberro, vice president of Catalan National Assembly, said: "We can say that pro-independence forces have won the elections."
He told a crowd gathered in Barcelona's Maritime Museum that "we demand the restitution of the (Catalan) government and the release of the political prisoners".
Electoral board authorities said the anti-independence Ciutadans (Citizens) party, led by lawyer Ines Arrimadas, is likely to win the highest number of votes for a single party, and 35 seats in the 135-member chamber.
But the victory will not be enough for her to hold a majority in the parliament.
Puigdemont would garner 34 seats for the Together for Catalonia group and in third place would be the pro-secession leftist republican ERC party with 32 seats, authorities said.
With the help of the radical pro-independence radical CUP party, which could get four seats, the pro-secession bloc is set to regain a majority in parliament.
The regional election is being closely watched in and outside Catalonia as a crucial test of strength for the region's powerful secession movement.
The vote was called by Spain's central government after it seized control of the northeastern region in late October following an "illegal"independence referendum called by the region’s former leaders.
The referendum was won by the secessionists, but the central authorities moved to dissolve the Catalan parliament and impose direct rule from Madrid.
Many of the independence movement’s leaders subsequently fled or have been jailed.
Oriol Junqueras, the former Catalan vice president and the leading candidate in the elections, mailed his ballot from a jail near Madrid, his left-republican ERC party said earlier this week.
Opinion polls ahead of the election have shown fugitive and jailed separatist candidates neck-and-neck in opinion polls with unionists, who claim to be in the best position to return Catalonia to stability and growth.
Following the events of October, many Catalans who had mixed feelings about independence, or did not care about the issue much, feel compelled to take a position.
Gabriel Brau, a 50-year-old photographer with little interest in politics, said he will vote for the first time since the 1980s, and it will be for one of the parties that favours independence - or rather, it will be against those that oppose.
During the October referendum, Spanish police using rubber bullets and truncheons against voters and formed human barriers to keep them out of polling stations.
"What happened on October 1 affected me in a powerful way," Brau said.
"I was thinking: 'What if they did that to my son?' That is not democracy. ... I don't want these people to govern my country."
Catalans who oppose independence - who previously kept a low profile - have also been energised.
Coming out as a unionist, they said, would have resulted in scorn, insults and even accusations of treason from pro-independence friends and neighbours.
But in the aftermath of the referendum they gathered for the first time in mass rallies similar in size to those achieved by the independence movement.
Cristina Calaco, 51, said she was so appalled by the way the secessionist leaders unilaterally pushed through the referendum, "I wanted to pack my bags and leave Catalonia".
After seeing unionists with Spanish flags on the streets, she was emboldened to publicly display her allegiance to Spain.
These days, when pro-independence neighbours bang pots and pans in noisy balcony protests, she said she opens her window and shouts "Viva Espana" - long live Spain.
Spain's heavy-handed response may have raised eyebrows in Europe, but it did not lead to any significant support for Catalan secession.
No European Union country has recognised the declaration of independence that Catalonia's parliament adopted on October 27.
On the surface, independence now seems further away than before the referendum. The Spanish government applied never-before-used constitutional powers take direct control of the region. The plan is to restore autonomy after Thursday's election produces a new regional government.
However, the Catalans supporting a total break-up with Spain now seem more committed than ever, saying the government's tough response showed the true nature of the Spanish state.
"They don't realise how many people they converted," said Ana Pousa, 38, who was born in the north-western Galicia region but grew up in Catalonia and now hesitates to call herself Spanish.
The movement for secession to a large extent is driven by the notion that Catalonia's history, culture and language make it separate from Spain. It is also a matter of economics: Wealthy Catalonia pays more taxes to Madrid than it gets back in government handouts, something that frustrated many Catalans during the deep recession which started in 2008.
But there is also a sense of victimhood that can be hard to grasp for outsiders.
Independence activists say they are being repressed by the Spanish government, drawing parallels to the dictatorship of Francisco Franco, when Catalans were banned from speaking their language in public.
On a square in Barcelona this week, some activists even made comparisons to the struggle against apartheid in South Africa.