Catalan leader Carles Puigdemont warned Thursday that a crisis over an independence drive by Catalonia's separatists would escalate if Spain goes ahead with plans to take over the wealthy's region's powers.

"To solve that the government has called an extraordinary serious situation, it will create an even more serious extraordinary situation by seizing Catalonia's political autonomy," he wrote in a letter to the Spanish senate which is poised to approve measures on Friday to take away Catalonia's powers