BARCELONA, Spain — The focus of the deepening clash between Catalan separatists and Spanish authorities is shifting to the regional parliament for a key session likely to include a historic declaration of independence that Spain has pledged to crush.

Catalan president Carles Puigdemont hasn’t revealed the precise message he will deliver Tuesday evening with separatist politicians expecting some sort of declaration based on the results of the disputed Oct. 1 referendum on independence.

At stake is the territorial integrity of Spain, threatened by a separatist movement that is sorely testing the strength of its constitution and the skill of its national and regional leaders.

Some expect a symbolic declaration, while others believe a full-scale break with Spain will be attempted, even as Spanish Prime Minister Mariano Rajoy vows he will use all lawful means to keep Spain intact.

The Spanish government’s staunch opposition, the lukewarm response of the international community to the prospect of a breakaway state in Europe, and the concerns of business leaders all suggest an independence move would extract a heavy price from Catalan’s separatist leaders.

Separatist politicians say there will be a declaration of independence for the northeastern region of 7.5 million people during the Tuesday session.

The Oct. 1 referendum vote has been followed by mass protests of Catalans angered by heavy-handed police tactics.

There also have been large-scale rallies in both Catalonia and Madrid by people committed to keeping Spain intact.