Spain's government on Tuesday warned Catalan president Carles Puigdemont "not to do anything irreversible" ahead of a speech in Barcelona in which the separatist leader could declare independence from Spain. 

"We call on Puigdemont not to do anything irreversible, not to pursue a path of no return and not to make any unilateral independence declaration, which would lead to illegality," government spokesman Inigo Mendez de Vigo told reporters.