BARCELONA, Spain — After a chaotic day of wavering, Catalonia’s separatist leader, Carles Puigdemont, announced on Thursday that he would place a decision on independence from Spain before the region’s Parliament.

The move by Mr. Puigdemont virtually ensures that the central government in Madrid will take control of the restive region, using its emergency constitutional powers following an expected approval vote on Friday in the Spanish Senate, where the conservative party of Prime Minister Mariano Rajoy holds a majority.

Mr. Puigdemont made the announcement before a scheduled appearance before the Catalan Parliament on Thursday evening. He said he had made the decision after failing to secure a commitment from the central government that it would not take control of the region if he called early elections.

“There are none of the guarantees that justify convening elections today,” Mr. Puigdemont said during a brief televised address from his government headquarters. “I tried to obtain the guarantees,” he said, but “I didn’t get a responsible answer from the Spanish government, which has instead used this option to add to the tension.”