BARCELONA • A fiercely secessionist leader has been elected president of the wealthy region of Catalonia, thanks to a last-minute show of unity, giving fresh impetus to attempts to leave Spain.

The appointment of Mr Carles Puigdemont, just hours before a deadline that would have forced a fourth set of polls since 2010, drew an instant rebuke from Spanish Prime Minister Mariano Rajoy.

"The government won't allow a single act that could harm the unity and sovereignty of Spain," Mr Rajoy warned in a live televised appearance on Sunday in Madrid.

His remarks came after Catalonia's pro-independence faction, which won regional parliamentary elections last September, finally came to an agreement this weekend over who should lead the new local government after three months of inter-party feuding.

The sticking point had been incumbent president Artur Mas, whom the far-left Popular Unity Candidacy or CUP, rejected. The separatist bloc did not have enough Parliament seats to form a government without the CUP.

In a surprise move, Mr Mas agreed to step aside last Saturday, naming Mr Puigdemont, 53, the mayor of Girona, as his successor.

Mr Puigdemont comes from a fervently pro-independence family. He has also been at the helm of an association of Catalan municipal leaders who favour independence.

"We need... to start the process to set up an independent state in Catalonia," he said in a speech to the region's Parliament on Sunday.

"I am fully aware that we are starting a process that is far from easy and far from comfortable, but we will put into it value and courage."

Mr Mas said he had made a painful decision, but insisted that he would remain in politics.

He hailed the last-ditch agreement, telling his party that in Madrid "all the alarm bells started ringing again".

AGENCE FRANCE-PRESSE, NEW YORK TIMES