Spain's government says it is studying the "viability" of the proposal by Catalonia's separatist leader to name former lawmakers who are in jail or fugitives from justice to his new Cabinet.

Spanish government official Jose Maria Jover said in a letter to the regional Catalan government Sunday that without the central government's authorization, the four proposed Cabinet members won't be able to take their posts.

New Catalan leader Quim Torra named Jordi Turull and Josep Rull, who are both in pre-trial detention, and Antoni Comin and Lluis Puig, who are fugitives in Belgium, as proposed members of his government on Saturday.

All four were members of the previous Catalonia government and removed by Spanish Prime Minister Mariano Rajoy following an illegal declaration of independence by regional lawmakers in October.