The regional parliament of northeastern Catalonia is due to vote on a proposal by secessionist parties that hold a majority in the chamber to set up a road map for independence from Spain by 2017.

The initiative defies Spain's central government, which considers it unconstitutional. A debate preceding the vote is set to begin at 0900 GMT (4 a.m. EST) Monday.

Prime Minister Mariano Rajoy's government has pledged to take legal action against the Barcelona-based parliament if it approves the proposal.

Although Catalan branches of Spain's ruling conservative Popular Party and the Socialist and the Citizens opposition parties filed appeals to halt the vote, Spain's Constitutional Court ruled Thursday that it could go ahead.