Spanish Prime Minister Mariano Rajoy has said regional elections next month in Catalonia will help end "separatist havoc" in the north-eastern region.
He addressed a campaign event on his first visit there since imposing direct rule on the region a fortnight ago.
Defending his decision in Barcelona, he said he had "exhausted all roads" after the Catalan government's unilateral declaration of independence last month.
Several key Catalan leaders are currently being detained over the move.
Some 750,000 people protested in Barcelona on Saturday against the arrests, local police said.
The crisis was sparked by a disputed referendum held in Catalonia in October, which had been barred by the Spanish courts.
Catalan officials said the independence campaign won 92% of the vote, from a turnout of 43%. Many of those who were against independence did not cast votes, refusing to recognise the legitimacy of the referendum.
The Spanish government responded to the referendum by dissolving the Catalan parliament, imposing direct rule, and calling a snap regional election on 21 December.
Speaking at a campaign event in Barcelona for his Popular Party (PP) on Sunday, Mr Rajoy called on the participation of the "silent majority" to "convert their voice into a vote".
"We must recover Catalonia from the havoc of separatism," he added.
Since the crackdown by Madrid, Catalonia's sacked President Carles Puigdemont has gone into self-imposed exile in Belgium, and his top allies have been prosecuted.
A lawyer whose firm represents two of his imprisoned former ministers told BBC News that their situation had been made worse by Mr Puigdemont's decision to flee.