A central government official told The Associated Press that Spanish Prime Minister Mariano Rajoy has urged the country's top legal consultative body to review the bill. The official said Madrid is expected to challenge the law in the country's Constitutional Court on Thursday. The source asked not to be named in line with internal protocols.
Catalonia's renewed push for secession has opened one of Spain's deepest political and institutional crises of recent years. Although much of the blame has been put on the pro-independence bloc in the regional parliament, Rajoy's conservative government has been criticized for letting the situation get this far.
Puigdemont's government claims it has a democratic mandate to seek a binding independence referendum based on the universal right to self-determination. However, approval for the referendum law came after more than 11 hours of heated debate.
The support of 72 pro-independence lawmakers was enough to pass the measure, but 52 opposition members of parliament walked out in protest before the voting started. Eleven lawmakers abstained from voting.
The parliamentary debate in Barcelona saw tensions flare when the regional body's top speaker, Carme Forcadell, announced that a vote on the bill would proceed before the legislation had undergone the customary legal vetting. The vote had not appeared on the day's agenda until the very last minute.
Spain's public prosecutor announced it was readying legal paperwork to sue the speakers, including Forcadell, for disobeying previous Constitutional Court orders and for abusing power.
Ines Arrimadas, the leader of Ciudadanos (Citizens) —the main opposition party in Catalonia— also announced that she would seek parliamentary support for a no-confidence vote against Puigdemont in an effort to force new regional elections.
Spain's deputy prime minister made a televised appearance amid the chaos and numerous pauses in the meeting to announce that Rajoy's government was urging the Constitutional Court to take punitive measures against those who allowed the bill to be debated.
Soraya Saenz de Santamaria said Catalonia's parliament was holding a "fake debate" that she dubbed as an "embarrassing show" and "a kick to democracy, to Catalans and to political decency."
The Spanish government is trying to strike a delicate balance between offsetting the secessionist defiance and staying away from more dramatic measures that would further inflame anti-Spanish sentiments, such as suspending Catalonia's autonomous powers or declaring a state of emergency that would bring the army into the mix.
In a show of political unity at the national level, the leaders of the Socialists and the business-friendly Ciudadanos party held conversations with Rajoy on Wednesday. Both leaders had separate meetings scheduled with the prime minister on Thursday.
The Catalonia region centered on Barcelona generates a fifth of Spain's gross domestic product. It self-governs in several important areas, such as police, health and education. But key areas such as taxes, foreign affairs and most infrastructures are in the hands of the Spanish government.
Both Catalan and Spanish are spoken in the region of 7.5 million people, and many Catalans feel strongly about their cultural heritage and traditions.