Protesters said they would do anything they could to protect Catalonia’s regional president amid fears he would be jailed for advocating independence.
This included surrounding the parliament or any building Mr Puigdemont was in as a human shield against his arrest.
It raises the difficult possibility of further brutal clashes between separatists and the civil guard amid the increasing tensions.
Mr Puigdemont joined pro-independence Catalans who marched through Barcelona today as the region was left reeling after the Spanish government moved to take control.
Spain’s public prosecutor is currently preparing a lawsuit against Mr Puigdemont over the independence vote.
If he declares independence he is expected to be arrested for the crime of rebellion against the Spanish constitution.
He could be facing a prison sentence of up to 30 years.
The crime of rebellion is defined as an uprising designed to “repeal, suspend or totally or partially modify the Constitution” or “declare independence of a part of the national territory”.
The controversial referendum on Catalonia’s independence has been declared illegal and unconstitutional by Spanish authorities as separatists did not follow proper legal procedure in calling the vote.
News of the lawsuit came as Spain’s Prime Minister Mariano Rajoy invoked Article 155 of the Spanish constitution, taking control of the autonomous region this morning.
Mr Puigdemont and his ministers have all been deposed, with Spanish authorities stepping in to govern the province after a controversial independence referendum that saw 90 percent of voters opt to leave the Mediterranean kingdom.
Mr Rajoy’s government claims the referendum was conducted illegally and has seized power to ensure the rule of law.
After throwing out the current government, Mr Rajoy will trigger new regional elections within six months. Parliament will continue to sit until then.