Catalan leader Carles Puigdemont has delayed an announcement of plans for the future of the Spanish province.
There was speculation that he was about announce a unilateral declaration of independence from Spain following a disputed referendum.
But a session of the regional parliament was delayed by an hour, amid growing demands for him to drop plans to break away.
Reports say Catalan party leaders are meeting before the session begins.
Catalan police have been posted outside the parliament in Barcelona, sealing off the grounds to the public.
A large pro-independence rally is currently taking place in the area.
Earlier, the mayor of Barcelona has urged Mr Puigdemont and Spanish Prime Minister Mariano Rajoy to “de-escalate” the crisis.
The Madrid government called on the Catalan leader “not to do anything irreversible, not to pursue a path of no return and not to make any unilateral independence declaration”.
And the president of the EU’s European Council has appealed to him to respect Spain’s constitutional order.