The armed Basque separatist group Eta has declared that a ceasefire it called four months ago is now permanent and offered to make it verifiable by observers.

In a statement released to the Basque newspaper Gara the group said: "Eta has decided to declare a permanent and general ceasefire which will be verifiable by the international community.

"This is Eta's firm commitment towards a process to achieve a lasting resolution and towards an end to the armed confrontation."

The armed group said that the solution to Basque conflict "will come through the democratic process with dialogue and negotiation as its tools."

Rumours that Eta, classified as a terrorist group by the European Union, would take a step like this have been circulating for weeks. It declared a halt to "offensive armed actions" in September.

Observers warn that Eta has called permanent ceasefires before and has later called them off. The government of socialist prime minister, José Luis Rodríguez Zapatero, is sceptical about the group's intentions and has demanded that it simply declares it has given up violence once and for all.