Puigdemont said the Saturday decision by Prime Minister Mariano Rajoy to fire the regional government and force a new election, which will be effective next Friday, was "the worst attack against the institutions and the people of Catalonia since the military dictatorship of Francisco Franco".
In a televised announcement, Carles Puigdemont said Madrid was failing to respect the rule of law after Prime Minister Mariano Rajoy announced he would move to dismiss Catalonia's separatist executive, take control of regional ministries and call elections. He said a new regional election in Catalonia should be held in the next six months.
Spain's National Security Department said late on Friday that an undisclosed number of government websites had been hit in recent weeks with slogans supporting independence for the country's Catalonia region.
"There is no country in the world ready to allow this kind of situation within its borders", Rajoy said.
In a significant upping of the stakes in his bid to rein in the region's pro-independence rulers, Mr Rajoy has said that although the Catalan parliament will not be dissolved immediately, its functions will be limited to "avoid measures contrary to the Constitution".More news: Sensex crosses 32500; Nifty hits new high of 10227
Article 155 allows central authorities to intervene when one of Spain's 17 autonomous regions fails to comply with the law.
However, the Catalan leader called on the regional parliament to suspend the proclamation in order to make way for dialogue with Madrid.
The measures take the country into uncharted legal waters, and come just a day after Madrid won powerful backing from the king and the European Union in its battle to keep the country together.
Rajoy's Popular Party has a majority in the Senate.
Catalan president Carles Puigdemont was among the huge crowds filling the streets around the Paseo de Gracia boulevard, with many chanting "independence" and "freedom".More news: PM to attend centenary celebrations of Patna University, address gathering
"Spain needs to face up to an unacceptable secession attempt on its national territory, which it will resolve using legitimate democratic institutions, respecting our constitution, adhering to the values and principles of the parliamentary democracy in which we have lived for 39 years", Felipe said.
Mr Rajoy was notably scant on details and long on justification for direct rule in his speech, essentially limiting his much-anticipated package of specific measures to a broad-brushed description of the whys and wherefores for his government's substitution of the nationalist ministers.
In an effort to derail the independence movement led by the separatist politicians, Rajoy is also seeking the Senate's approval next week to assume the power to call a regional election - something that only Catalonia's top leader can do at the moment.
Puigdemont says he has a mandate to declare independence after the referendum, which his administration says resulted in a 90 percent Yes vote.
Spanish authorities are preparing to arrest Catalonia's president and charge him with rebellion if he declares independence.More news: Building Collapse in Southern India Reportedly Kills Six People
Amid the uncertainty, businesses have started to move their legal headquarters out of Catalonia, Spain's wealthiest region.