Unionist Citizens are still on course to be the biggest party - but the separatist parties might have the numbers to be able to form a coalition.

Here are the provisional results in terms of seats, external:

• Citizens - 36
• Together for Catalonia - 34
• Republican Left of Catalonia - 32
• Socialists - 17
• In Common We Can - 8
• Popular Unity - 4
• Popular Party - 4

There's a total of 135 seats in the Catalan parliament - 68 seats are needed for a majority.

A spokesman for Mr Rajoy's Popular Party, José Ramón García Hernández, says the message of the election is that it's time to talk.

"When a society is divided you cannot be the element of division, you have to be the element of union," he told the BBC World Service's Newshour programme.

"And I think we open a new era of dialogue, a real dialogue."

If you're just joining us, it appears the voters of Catalonia have returned separatist parties to power by a narrow margin, in a snub to Spanish Prime Minister Mariano Rajoy.

With more than 80% of votes counted, parties that favour independence are ahead. Interim turnout figures show a record number of people voted.

The election was called by Mr Rajoy's government, which deployed hitherto unused constitutional powers to assert control over the region.

Image source, AFP

One surprise in the partial official results is that Carles Puigdemont's list has overtaken its rival for the separatist crown, the ERC. The exit poll had put the ERC well ahead.

But there are still a lot of ballots to count.

With over 50% of the votes counted, external, the provisional results - in terms of seats - are the following:

• Citizens - 35
• Together for Catalonia - 34
• Republican Left of Catalonia - 32
• Socialists - 18
• In Common We Can - 8
• Popular Unity - 4
• Popular Party - 4

There's a total of 135 seats in the Catalan parliament - 68 seats are needed for a majority.

With 30% of votes counted, separatist parties are on course to win an absolute majority in the new Catalan parliament.

Image source, Reuters

If the exit poll proves anywhere accurate, then Spain's governing conservative Popular Party (PP) has fallen to a new low of 3-5 seats.

This could be a really bad night for the PP but it may turn out that many of their voters switched tactically to Citizens in order to ensure a strong showing for unionist parties.

Kevin Connolly, BBC Europe Correspondent

Image source, EPA

Counting is under way in an election that will shape the immediate political future here in Catalonia and have a huge impact in wider Spanish society.

The poll was called by the Spanish government to resolve a constitutional crisis triggered by the region's unlawful independence referendum in October.

Turnout figures suggest that supporters and opponents of independence alike recognise the magnitude of what's at stake.

For both sides in Catalonia, the problem is that there's no guarantee this election will resolve the region's constitutional crisis.

If the new parliament is evenly balanced between unionists and separatists, the search for a solution will continue.

Image source, AFP

If the Republican Left of Catalonia (ERC) ends up as the largest separatist party, it raises questions about whether Carles Puigdemont, who leads a rival party, can return as the region's leader, even if he were free to do so.

The ERC's own leader, Oriol Junqueras, is on remand, facing Spanish charges over the independence declaration in October.

News crews are waiting to hear reaction from Catalonia's sacked leader, Carles Puigdemont.

At the September 2015 election, the separatist parties managed to secure a majority to govern the region but it was complicated.

The mainstream separatist parties ran as a united list – Together for Yes - but failed to win an overall majority and, once in government, had to rely on a confidence-and-supply agreement with the anti-EU CUP.

If the exit poll from La Vanguardia is anything like the final result in Catalonia, it could pose an interesting question as to who has the right to form the region's next government.

Normally, the largest party has the right to have the first stab at forming a government - according to the exit poll, this would probably be the unionist party Citizens.

However, the separatist parties may insist they have the right to try first, if they have the largest number of seats overall.

Catalonia's El Nacional news site, which is strongly pro-independence, has a handy breakdown in English of the findings in La Vanguardia's poll.

The poll was based on 3,200 telephone surveys carried out up until 19:00 (18:00 GMT) today.