The parliament of Spain's autonomous Basque region has voted in favour of a proposal to loosen ties with the central government in Madrid.
The plan would give extra powers to the region
MPs backed a plan to change the Basque Country's status to that of a "free association" with Spain.
The plan will now go before national parliament, where correspondents say it faces certain rejection.
Basque separatists have been fighting an armed campaign for an independent Basque homeland since the 1960s.
Basque Prime Minister Juan Jose Ibarretxe told parliament before the vote the Basque people had a right to decide their own future.
The controversial plan was unexpectedly adopted with 39 votes in favour and 35 against after three members from the Socialista Abertzaleak party, considered to have links with ETA separatists, gave it their backing.
The party had originally said the plan does not go far enough.
As well as changing the Basque region's relationship with Madrid, the proposal would also give the region its own court system and representation on international bodies, such as the European Union.
The Basques presently have control over their finances, police, schools, healthcare and other public
Spain's ruling Socialists and opposition Popular Party are both strongly opposed to the plan.
But Mr Ibarretxe has said he intends to call the Spanish Prime Minister, Jose Luis Rodriguez Zapatero, to try to open negotiations.