Three backers of Catalonia's independence have sought to secure release from jail for their role in the region's push to break from Spain which triggered the country's worst political crisis in decades.

Spain's top court has officially ruled that Catalonia's disputed independence referendum was illegal because a regional law that backed it was against Spain's constitution.

Protesters are gathering for a fresh round of demonstrations in Barcelona to demand the release of two leaders of Catalonia's pro-independence movement who were jailed in a sedition probe.

A Spanish judge has ordered two leaders of Catalonia's pro-independence movement jailed while they are investigated on possible charges of sedition.

A top Spanish government official in Catalonia has expressed regret about those injured when police cracked down on people taking part in a banned referendum.