Three Catalan independence leaders being held in pre-trial detention have complained to a UN panel that their imprisonment breaks international law, their lawyer said on Thursday.
The former deputy leader of the Catalan regional government and leaders of two separatist groups are accused of sedition for their bid to declare Catalonia independent from Spain.
While other figures behind last year's referendum and independence declaration - both acts declared illegal by Madrid - fled to Brussels, Oriol Junqueras, Jordi Sanchez and Jordi Cuixart were arrested and denied bail pending their trial.
"Their detention by Spain is an affront to human rights, designed to prevent them from performing their role as political representatives of the Catalan people," their lawyer, Ben Emmerson, said in a statement ahead of a news conference in London.
Emmerson has filed their complaint with the UN Working Group on Arbitrary Detention, a panel of human rights experts that can publish non-binding recommendations to governments if it finds they failed to follow due process.
The case does not ask the panel to consider the issue of Catalan independence but seeks its affirmation that governments cannot repress political dissent through arbitrary detention, Emmerson said.
After imposing direct rule on the northeastern region in October, Spanish Prime Minister Mariano Rajoy called regional elections in December to try to defuse a crisis that threatened to split the country.
But his gamble backfired when separatist parties won a majority, giving new impetus to the independence movement, led by Carles Puigdemont, who remains a fugitive from justice in Belgium.