Catalonia will move on Monday to declare independence from Spain after holding a banned referendum, pushing the nation towards a rupture that threatens the foundations of the European Union.

Catalan President Carles Puigdemont said he favoured mediation to find a way out of the crisis but that Spain’s central government had rejected this.

Prime Minister Mariano Rajoy’s government responded by calling on Catalonia to “return to the path of law” first before any negotiations.

Mireia Boya, a Catalan MP from the pro-independence Popular Unity Candidacy party, said a declaration of independence would follow a parliamentary session on Monday to evaluate the results of the October 1 vote to break away.

“We know that there may be disbarments, arrests … But we are prepared and in no case will it be stopped,” she said on Twitter.

Puigdemont told the BBC he would ask the region’s parliament to declare independence following the referendum, which Spain’s government and constitutional court say was illegal and in which only a minority of Catalans voted.

In a TV address on Wednesday night, Puigdemont said: “This moment calls for mediation. We have received various offers in the last hours and we will receive more.”

Rajoy’s government replied that Puigdemont had wasted an opportunity to put Catalonia back on a legal course.

Participants in the referendum opted overwhelmingly for independence but turnout was only about 43 per cent as Catalans who favour remaining part of Spain mainly boycotted the ballot.

Puigdemont also criticised Spain’s King Felipe VI, who on Tuesday lambasted the “irresponsible behaviour” of the Catalan leaders.

The EU executive called again on Wednesday for the Spanish government and Catalan authorities to open a dialogue.