Spaniards lined the streets of Madrid carrying national flags as unionists used the holiday military parade to show unity in the face of moves by Catalonia to declare independence.
The wealthy region's intention to break away has plunged Spain into its worst political crisis since an attempted military coup in 1981.
Spain';s Prime Minister Mariano Rajoy gestures as he delivers a statement at the Moncloa Palace in Madrid, Oct. 11, 2017.
Prime Minister Mariano Rajoy issued Wednesday an ultimatum to Catalonian President Carles Puigdemont to clarify by Monday whether he has formally declared independence for the northeastern region.
If Puigdemont confirms that he did, indeed, declare Catalonia's independence, then Rajoy has vowed to trigger within several days Article 155 of Spain's constitution to suspend Catalonia's semi-autonomy and impose direct rule.
Catalan President Carles Puigdemont signs a declaration of independence at the Catalan regional parliament in Barcelona, Spain, Oct. 10, 2017.
A majority of Catalonians voted to breakaway from Spain in an October 1 referendum. Puigdemont proclaimed Catalonia's independence on Tuesday during a speech before the region's parliament, but froze its implementation for several weeks to allow for negotiations between the separatists and the Madrid government.
The stakes are high. Spain could lose about one-fifth of its economic output and more than 25 percent of its exports if Catalonia secedes.
Stewart King, a senior lecturer in Spanish and Catalan culture and language at Australia's Monash University, told VOA's Victor Beattie that if Puigdemont does not follow through with formal independence, the junior political party that makes up his ruling coalition government could withdraw its support and cause parliament to collapse.
Spain';s King Felipe reviews the guard during a military parade marking Spain';s National Day in Madrid, Oct. 12, 2017.
Rajoy joined King Felipe the Sixth in observing the traditional military parade in Madrid that marks explorer Christopher Columbus's arrival in the Americas in 1492.
VOA's Victor Beattie in Washington DC contributed to this report.