Exit polls from elections in Spain's northeastern region of Catalonia show the majority of local parliamentary seats will go to nationalist parties that favor independence from Spain.

Early returns from Sunday's vote show the national alliance of incumbent regional president and pro-independence candidate Artur Mas has taken at least 48 seats in the 135-seat parliament, down from its current total of 62. The separatist Republican Left (ERC) doubled its share to around 20 seats.

Both parties have pledged to hold a referendum asking Catalans if they wish to split from Spain, a move the central government says would be unconstitutional.

The Socialist party (PSC), which does not favor independence, took 25 seats in the vote.

The Mas government called early elections as part of a power struggle with the central government run by Prime Minister Mariano Rajoy.

Catalonia, which is home to factories, banks and other industries, is responsible for around one-fifth of Spain's economic output.

Many Catalans believe the central government gives back too little, considering the region's contributions.