Spain's government has lodged a legal bid to stop Catalonia holding an independence referendum, asking the Constitutional Court to veto moves by the regional assembly, Prime Minister Mariano Rajoy said on Friday.
"There will not be any referendum on October 1," Rajoy told a news conference in Madrid after his weekly cabinet meeting.
The stand off between Madrid and Barcelona is likely to intensify in the coming weeks as Catalonia's separatist government moves ahead with the vote on breaking with the rest of Spain.
On Wednesday, Catalan lawmakers gave themselves powers to fast track some laws and preparations for the referendum.
Rajoy said his government had filed a legal bid to block to those reforms with the Constitutional Court, which has previously ruled against secessionist challenges.
Catalonia, a wealthy, populous region in the northeast with its own language and distinct culture, has long harboured an independence movement which grew in intensity during an economic crisis. Pro-secession parties now control its assembly.
Last week the Spanish government told Catalonia it would lose access to some public funds if it uses state money to organise the referendum, and vowed to increase controls on spending.
It is unclear exactly how the vote will happen if, as expected, Spain's Constitutional Court keeps striking down attempts to organise it.
Civil servants such as police officers face a dilemma if the referendum does go ahead, as they risk sanctions from authorities in both Barcelona and in Madrid for not following their commands.
Rajoy, who has been criticised for his inflexible stance on the issue, said he was ready to talk with Barcelona.
"I've always been prepared to have a dialogue over the best way to work with Catalonia's institutions to everyone's benefit," Rajoy said. "I've always been prepared to do that and I am today."
Catalonia's majority separatist lawmakers approved a reform Wednesday to fast-track bills through parliament, a move they hope will pave the way to holding an independence referendum banned by Madrid.
The vote came as the stand off between the Spanish region's pro-independence government and Madrid reached such heights that opposition MPs have dubbed it unprecedented and an attack on democratic rights.
The reform, passed with 72 votes for and 63 against, means that any piece of legislation in Catalonia can now be adopted quickly, with fewer checks and balances.
The idea is to circumvent any legal and practical challenges from Madrid to organising the referendum.
But Wednesday's adoption of the fast track reform has drawn sharp criticism from opposition deputies.
Catalonia's Socialists accused those who voted for it of "trampling on the democratic rights of the lawmakers and citizens they represent."
The move is only the latest in a long list of defiant announcements, threats and legal challenges from both Madrid and the Catalan executives over its independence drive.
Catalan leaders pledge to hold the binding vote on October 1 – come what may, though how they will do so remains unclear.
Joaquim Forn, Catalonia's new minister in charge of interior affairs and a staunch separatist, said last week that the region's police squad would not stand in the way of people voting, even if the referendum is illegal.
Then in an interview with French daily Le Figaro on Monday, Catalonia's President Carles Puigdemont said that nothing would stop the region from voting.
"No suspension, no threat will stop the Catalans from deciding their future in a democratic way," he said, referring to speculation that Madrid could remove him from office for disobedience.