The governing body of the assembly voted last month to admit for processing the initiative put forward by the tiny Catalan Solidarity for Independence electoral coalition, which has no representation in the regional parliament.

The wealthy northeastern region, which is governed by separatist party ERC, staged a failed unilateral bid for independence in 2017 that triggered Spain’s worse political crisis in decades.

Spain’s central government will challenge the citizens’ initiative proposal in the Constitutional Court, a move that will “immediately paralyse” its processing in the Catalan regional assembly, Justice Minister Felix Bolanos told a news conference after a weekly cabinet meeting.

The government “opposes any law that is divisive, that fractures society, that generates complaints, that generates social and political divisions,” he added.

Socialist Prime Minister Pedro Sánchez’s minority coalition government depends on Catalan separatist parties in the national parliament to pass legislation, and the court challenge is likely to raise tensions with these formations.

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It comes as Catalonia is gearing up for an early regional election on May 12 that polls suggest will be tight.

A survey published last week by regional polling firm CEO put the Catalan branch of Sánchez’s Socialist party in the lead, with a tight race for second place between the ruling ERC and the more hardline separatists JxCat.

The poll also showed support for independence has waned since the failed 2017 secession bid, with 51 percent of Catalans opposed and 42 percent in favour.