Sacked Catalan leader Carles Puigdemont has called for "democratic opposition" to direct rule from Madrid by Spain's government.
He promised to continue to "work to build a free country".
Mr Puigdemont made the call in a TV address broadcast from an undisclosed location.
The Spanish government has stripped Catalonia of its autonomy and taken charge of its government.
The measures came early on Saturday after the Catalan parliament voted to declare independence on Friday.
An official state bulletin dismissed Catalan leaders and handed control of Catalonia to Spain's Deputy Prime Minister, Soraya Saenz de Santamaria.
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