Those measures could include taking over the regional government's powers, a move that could deepen the country's worst political crisis in a generation. "We will do everything that legislation allows us to ensure this", Rajoy told the German newspaper Die Welt.
Benet Salellas of the separatist Catalan CUP party said: 'It's very clear to me that those who I represent won't accept any other scenario'.
Paris, Oct 9 Catalan independence would not enjoy global recognition, France's minister for European affairs said today as the Spanish region's leader threatens to announce a split.
"The exit of many companies from Catalonia is the effect of the irrational and radical policies implemented and pursued by the (regional) government", minister Luis de Guindos said as he arrived for a meeting of euro zone finance ministers in Luxembourg.
Spain also sought to reassure worldwide investors concerned about the political situation in the country.
Ms Colau also urged Prime Minister Mariano Rajoy to pull out the extra police that have been drafted in to the northeast region as a "gesture of state responsibility".
European Economics Commissioner Pierre Moscovici, asked about the economic impact of the Catalan debate, said the Spanish constitutional order must be respected.
IG analyst Chris Beauchamp says a positive beginning of the week for the Spanish Ibex 35 index suggests investors are confident there will be a resolution to the crisis.
Catalonia, a northeastern region about the size of Belgium, is home to 7.5 million people and accounts for a fifth of Spain's economy.
Tensions soared after police cracked down on voters during the banned October 1 independence referendum, prompting separatist leaders to warn they would unilaterally declare independence.
France's minister of European affairs said Monday if Catalonia declares independence, France won't recognize it as a state.
Catalan regional president Carles Puigdemont will address the Catalan parliament on Tuesday evening following the disputed referendum won by the "Yes" side.
However, hundreds of thousands of people have turned out for anti-independence rallies, including in Catalonia's capital, Barcelona, since the vote.
Although it is not know what Puigdemont might say, any declaration of independence from the region would likely lead to more violence.
But Rajoy assured Catalan leaders that there "is still time" to backtrack and avoid the imposition of direct rule.
Spain called the referendum illegal and police in riot gear moved in on the day of the vote to try to forcibly shut it down, firing rubber bullets at unarmed protesters.