BARCELONA, Spain -- A senior European Union official has pleaded with the Catalan leadership to step away from the brink of a divisive call for independence and resort to dialogue with Spain's government instead.

European Council President Donald Tusk addressed Catalonia's president directly, hours before Carles Puigdemont is expected to make an announcement on the region's bid for secession.

Tusk said in Brussels that "I ask you to respect in your intentions the constitutional order and not to announce a decision that would make such a dialogue impossible."

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Tusk added that "diversity should not and need not lead to conflict whose consequences would obviously be bad for the Catalans, for Spain and for the whole of Europe."

Before a meeting of the EU's Committee of the Regions, Tusk said that "let us always look for what unites us and not for what divides us. This is what will decide the future of our continent."

Catalonia's regional leader was addressing parliament Tuesday in a highly anticipated session that could spell the birth of a new republic, marking a critical point in a decade-long standoff between Catalan separatists and Spain's central authorities.

Security was tight in Barcelona and police cordoned a park surrounding the legislative building, where the Catalan President Carles Puigdemont is expected to walk a fine line when he addresses regional lawmakers.

Catalan President Carles Puigdemont presides over a cabinet meeting at the regional government headquarters, the Generalitat, in Barcelona, Spain October 10, 2017. REUTERS

The speech will need to appease the most radical separatist-minded supporters of his ruling coalition - but Puigdemont faces shutting down any possibility of negotiating with Spain if he adopts a hard line.

The Catalan leader hasn't revealed the precise message he will deliver in the address at 6 p.m. (1600GMT), but separatist lawmakers and activists have said they won't be satisfied with anything short of an independence declaration.

A full declaration of secession -or an outright proclamation of a new Catalan Republic - would certainly be met with fierce opposition by central Spanish authorities, who could take the unprecedented step of suspending the self-government of Catalonia and taking over some or all powers in the region.

Puigdemont himself could end up in prison.

Some 2.3 million Catalans - or 43 percent of the electorate in the north-eastern region - turned out to vote in the Oct. 1 independence referendum, which the Spanish government said was illegal. Regional authorities say 90 percent who voted were in favour and declared the results of the vote valid.

The ballot was marred by violence as riot police tasked with stopping the voting clashed with voters, leaving hundreds injured.

The political deadlock has been compared in Spain to a "train collision" and has plunged the country into its deepest political crisis in more than four decades, since democratic rule was restored following the dictatorship of Gen. Francisco Franco.

In the streets of Barcelona, expectations were divided between those who want to see the birth of a new nation and others opposed to the idea. Some feared a drastic backlash from the Spanish central authorities.

"I am thrilled," said Maria Redon, a 51-year-old office worker. "I've been waiting for this all my life. We have fought a lot to see an independent Catalonia."

But Carlos Gabriel, a 36-year-old waiter, said that is "impossible."

"He won't do it. By doing so he would be diving into an empty pool," he said referring to Puigdemont's parliamentary address. "These people know it's just a dream. Something very complicated. Something that will carry many negative consequences for all of us."

In Catalonia and elsewhere in Spain, people were reading between the lines of politicians' statements to try to figure out what's next.

Regional government spokesman Jordi Turull refused to comment on what Puigdemont's address would be about during a press conference on Tuesday.

The Catalan parliament's governing board acknowledged Tuesday morning it had received the results in last week's disputed independence referendum. But a parliamentary official who spoke on condition of anonymity said the board refrained from putting the results through normal parliamentary procedures to elude any legal problems, because the referendum and its legal framework have been suspended by the national Constitutional Court.

Assemblea Nacional Catalan and Omnium Cultural, two of the main civil society organizations driving the secession bid, have called for people to gather near Barcelona's parliament building to back the regional government in "welcoming the republic."

Hundreds of thousands have turned out for street protests in Barcelona and other towns in the past month to back Catalan independence and protest against alleged police violence during the vote. Those committed to national unity have also staged separate, large-scale rallies.

The tension has impacted the economy, with dozens of companies already relocating their corporate address away from the troubled region to remain under Spanish and European laws if Catalonia manages to secede. The moves of the firms' bases do not so far affect jobs or investments - but they don't send a message of confidence in the Puigdemont government.

Spain's Economy Minister Luis de Guindos said on Tuesday he hoped "common sense" would prevail and blamed Puigemont's "radical" and "irresponsible" government for the current standoff.

"This is not about independence, yes or no. This is about a rebellion against the rule of law," de Guindos told reporters in Luxembourg, where he was meeting with European Union ministers. "And the rule of law is the foundation of coexistence, not only in Spain but in Europe."