The Spanish news media had reported that Mr. Puigdemont had left Catalonia with five other deposed members of his cabinet, traveled by car to the southern French city of Marseille, and then by plane to Brussels.
In Spain, officials from Prime Minister Mariano Rajoy’s conservative Popular Party said their priority on Monday was to make sure Mr. Puigdemont did not try to stay in office, by insisting he remained leader of Catalonia, rather than worry about him escaping the country.
Fernando Martínez-Maíllo, a senior Popular Party official, characterized Mr. Puigdemont’s departure as “a desperate act.”
Albert Rivera, the leader of the Ciudadanos party, which is strongly opposed to secession, accused Mr. Puigdemont and his separatist leadership of “fleeing the country” while leaving his Catalan civil servants to resist and continue to break Spanish law.
Indeed, the forcible steps by the central government have now left Catalan civil servants and politicians with the painful choice of sticking to their secessionist plans and defying Madrid’s direct administration or facing the potential of criminal charges.
Not least, there was the important decision for separatist parties about whether to take part in regional elections called by Madrid or to risk sidelining themselves.
The two main Catalan parties — including Mr. Puigdemont’s Catalan European Democratic Party — said on Monday they would run in the elections, which are scheduled for Dec. 21, although perhaps no longer as part of the coalition that won the most parliamentary seats in 2015.
Germà Bel, a separatist Catalan lawmaker, said Mr. Puigdemont’s possible hopes of running a government from exile was “symbolic.”
“I don’t know of anyone who’s run a government from overseas,” he said. “Even Charles de Gaulle didn’t run a government from overseas.”
But he argued that it would be hard for Mr. Rajoy’s government to maintain control over Catalonia for an extended period.
The decision by pro-independence parties to take part in the December elections meant that they “at least implicitly” accept they are still part of Spain — no small concession.
“This election has been called by the Spanish government under Spanish law — and it will be an election run within the state,” Mr. Bel said.
With the emergency measures taken over the weekend, Mr. Rajoy opted not to appoint a caretaker leader of Catalonia.
Instead, the country’s deputy prime minister, Soraya Sáenz de Santamaría, took over the management of the Catalan administration from Madrid, and dispatched a senior central government official to Barcelona on Monday.
Juan Ignacio Zoido, the Spanish interior minister, said on Monday that the takeover of the Catalan police force, known as the Mossos, had gone smoothly. He fired the Mossos police chief,
Josep Lluís Trapero, over the weekend and appointed the deputy leader of the force, Ferran López, to the post.
Under the emergency measures allowed by
Article 155 of the Spanish Constitution, the provision invoked by Mr. Rajoy to take control of Catalonia, the national government could replace the 17,000 officers of the Mossos with Spanish police officers.
But Mr. Zoido said that “at no point did we consider eliminating the Mossos police corps.”
Mr. Zoido called on separatist leaders to remove their personal belongings from their offices on Monday and to leave, focusing solely on preparing for the December elections, as candidates.