Torra's swearing-in ceremony only lasted a few minutes and the central government decided not to send any representatives in a sign of tensions between the two.

Quim Torra, Catalonia's new separatist leader, was sworn in Thursday in a brief ceremony minus central government representatives during which he avoided promising to obey the constitution and pledged instead to follow "the will of the Catalan people."

"I promise to loyally fulfill the duties of the post of regional president being faithful to the will of the Catalan people represented by the Catalan parliament," he said, using the same formula as his predecessor and mentor Carles Puigdemont.

The 55-year-old did not promise to obey the statute that regulates Catalonia's autonomy, either. He appeared flanked only by a Catalan flag –without the traditional Spanish flag and portrait of the king that protocol states must be present – in a small side-room of the regional government building in Barcelona.

The ceremony marks the end of almost seven months of political limbo in this region of northeastern Spain, which has been under direct rule by Madrid since it deposed Puigdemont after a failed declaration of independence on October 27.

Torra, a hardline separatist, was handpicked by Puigdemont, who is currently in Berlin awaiting potential extradition to Spain and faces jail on charges of rebellion and misuse of public funds.

Torra has stressed he is merely a "caretaker president" as he awaits the return of Puigdemont, whom he considers the "legitimate" leader. In the meantime, he has pledged to keep fighting for independence. 

As a deferential gesture towards Puigdemont, Torra did not put on the medallion that regional presidents usually wear when they are sworn in.

There were no representatives of political parties or civil society, either. Only a few people close to Torra were present, along with regional parliamentary speaker Roger Torrent, a top regional government official and the head of the Catalan police.