The president of Catalonia, Carles Puigdemont, said he would abide by the Spanish province's independence vote but then said the official declaration would be suspended to allow time for tensions to "de-escalate" and dialogue to begin.
Addressing the Catalan parliament in Barcelona, Mr Puigdemont told the hushed gathering, "The will of the people must be respected. The ballots said yes and this is the way to go forward."
One side of the parliament chamber burst into applause while the other half looked stunned.
But Mr Puigdemont went on to say that the full declaration of independence would be suspended for a week so that tempers could cool and discussions begin. But he stressed that with a landslide victory for the 'yes' vote, he had a clear mandate to proceed towards independence for the north-eastern region .
"We have won the right to be independent and respected," he said.
In a long - and much-delayed - speech, Mr Puigdemont berated Spain's "aggressive" behaviour during the referendum on October 1, which was marked by violence on the part of the police towards people trying to cast their ballots in a referendum which the Madrid government branded unconstitutional. By extension, he also criticised the Spanish king who, in his own speech after the referendum, had castigated the referendum.
"The objective [of the Madrid authorities] was not just to take the ballot boxes but to create panic and fear," Mr Puigdemont said. "But they did not achieve their objective."
Two million people had gone out to vote and there were at least 770,000 more votes which could not be counted because of disruption on polling day, he said.
He traced the history of Catalonia's independence movement through the ages and acknowledged that in the 1970s, after 40 years of isolation under the fascist regime of General Franco, Catalonia was as eager as the rest of the country to embrace democracy. But, he said, Catalans "have won the right to be independent and respected."
He said, "The Spanish government has behaved in a very aggressive way. The only way to keep our values is for Catalonia to establish a separate entity."
In the days since the referendum, the world had taken notice of Catalonia, Mr Puigdemont said. "People are listening to us around the world.... This goes beyond a domestic affair."
But that did not mean the end of a close relationship with Spain, he added. "I want to transmit a message of serenity and respect, " he said and asked Madrid to accept mediation and end the political stand-off. Catalonia had nothing against Spain or the Spaniards and wanted only that each understands the other better, he said.
He recommended the outright declaration of independence should be suspended for some weeks "to initiate dialogue".
The opposition leader in the Catalan parliament slammed Mr Puigdemont's speech and his claim of a mandate, branding it "a coup" that would find no support in Europe.
Opposition leader Ines Arrimadas of the Ciudadanos (Citizens) party said the majority of Catalans feel they are Catalans, Spanish and European and that they won't let regional officials "break their hearts".
Outside in downtown Barcelona, the streets were packed with demonstrators both for and against the split from Spain. Security was tight and police immediately took action after Mr Puigdemont made his landmark speech.
As well as stretching out the hand of friendship to Spain, Mr Puigdemont also suggested the European Union should be involved in the talks and sought to reassure businesses that are leaving the region.
"The violence [in the referendum] will have economic effects," he said. "Companies are going away. But we are not going to destabilise things. We defend tolerance and we are always willing to talk."
A few hours after the speech, Catalan lawmakers signed a document they are calling a declaration of independence from Spain, despite the delay to its implementation.
Regional president Carles Puigdemont was the first to sign the document titled "Declaration of the Representatives of Catalonia." After him, dozens of other lawmakers signed it.
The Spanish government was quick to reject Catalonia's "tacit" independence declaration on Tuesday.
A central government spokesperson told AFP: "It's unacceptable to make a tacit declaration of independence to then suspend it in an explicit manner."