Several hundred thousand people demanding an independent Catalonia have joined hands to form a 400-kilometer (250-mile) human chain across the northeastern region of Spain.

The demonstration Wednesday aimed to illustrate local support for political efforts to break away from Spain. Organizers estimated about 400,000 people took part in the human chain.

Catalonia claims a deep cultural difference based on its language, which is spoken side-by-side with Spanish in the wealthy region.

Catalonia's regional leader Artur Mas has promised to hold a referendum on independence in 2014, but the Madrid-based government has said that such a vote would be unconstitutional.

Polls indicate that the majority of Catalans agree on holding a referendum, though surveys in the region of 7.5 million people indicate support for independence is around 50 percent.