MADRID (AP) — Hundreds of pro-independence supporters in Catalonia are protesting outside a courthouse to demand the release of regional government officials arrested in a crackdown by Spanish authorities over a planned secession referendum.

The protest Friday in the northeastern Catalan town of Hospitalet de Llobregat is an extension of another started Thursday outside the Catalan judiciary headquarters in nearby Barcelona that attracted thousands. A pro-independence group says that about 2,500 supporters were attending the protest in Hospitalet.

Many of the demonstrators in Barcelona had slept overnight near the judiciary building in tents or hammocks strung up between lampposts.

The Catalan National Assembly civic group has called for the protests to continue until the near dozen officials detained Wednesday are released.

Spain's central government says the planned Oct. 1 referendum is illegal.