Further adding to tensions, unions and Catalan associations called a region-wide strike for Tuesday due to "the grave violation of rights and freedoms", urging people to take to the streets.
"Spain will maintain that this vote is not legitimate but the strength of feeling demonstrated can not be ignored by Spain, nor by the wider European and worldwide community", said Fiona Hyslop, Scotland's minister for external affairs. The Catalan government said that around 2.26 million of the region's 5.34 million voters were able to cast their vote on Sunday.
Spanish Justice Minister Rafael Catalá said that the constitution of Spain gives the country the right to intervene and run a region, like Catalonia, if they declare independence.
During the vote, 33 police officers were also injured, local medical officials said. Some 900 people were injured on polling day when police fired rubber bullets and charged at crowds with truncheons to disrupt the vote.
Spain's world number one Rafael Nadal and Manchester City manager Pep Guardiola have spoken out following Catalonia's independence referendum on Sunday, which was marred by violence.
The central government and national courts considered the referendum illegal.
Legalities aside, the European Commission noted "there are times for unity and stability, not for division and fragmentation", and "violence can never be an instrument in politics". The European Union has also said that an independent Catalonia can not stay in the bloc, but must apply to join, a lengthy uncertain process.
On Wednesday, Spain's National Court said it was investigating two officials in Catalonia's police force for sedition in connection with violent protests in September.
Mr Puigdemont has called for mediation by the European Union to resolve the stand-off with Madrid, saying: "It is not a domestic matter".
Speaking shortly before a blistering attack on Catalonia's politicians by Spain's King Felipe, Mr Puigdemont said his government would "act at the end of this week or the beginning of next".