Spanish Deputy Prime Minister Soraya Saenz de Santamaria said Monday that Catalonian leader Carles Puigdemont has until Thursday to clarify his position on independence. The statement came as Puigdemont presented a letter to Madrid calling for negotiations, after having signed a symbolic declaration of independence last week.

Puigdemont’s letter to Spanish President Mariano Rajoy said Catalonia’s “suspension of the political mandate given by the polls on 1 October demonstrates our firm will to find a solution and not confrontation,” the BBC reports.

“For the next two months, our main objective is to bring you to dialogue,” the letter insisted.

“Let’s not let the situation deteriorate further. With good will, recognising the problem and facing it head on, I am sure we can find the path to a solution,” Mr Puigdemont added.

Madrid considers the vote to have been unconstitutional and invalid on its face. Ms Saenz Santamaria’s comments came in lieu of a response from Rajoy, who refused to address the letter directly.

Article 155 of the Spanish constitution allows for Madrid to take any “necessary measures” to impose direct rule in the event of a crisis, but has never been invoked. Such a move could be launched by Spain’s upper house of parliament, currently controlled by President Rajoy’s conservative Popular Party.

The government could also choose to take steps short of ousting Catalonia’s government, applying pressure by squeezing the region’s financing, as the Financial Times notes. Analysts and politicians reportedly see the triggering of article 155 as increasingly likely.

All of this will only further solidify Catalan opposition to Madrid, which by some accounts was relatively mild before the crisis. As Asia Unhedged reported last month, according to a local Catalonian poll, the majority of the region’s voters opposed outright independence from Spain before the referendum. That fact was complicated by the reality that those opposed were unmotivated to go to the polls. Madrid’s heavy-handed crackdown on the local government ahead of and during the vote has likely tipped the scales dramatically in favor of separatists. The triggering of Article 155 would only heighten the tensions even more.