|More than 800 people have been killed in Eta's four-decades-long campaign for independence [GALLO/GETTY]
Eta, the Basque separatist armed group, has declared a ceasefire in a video statement.
The video, issued on the Basque newspaper Gara's website on Sunday, showed three men speaking in Basque.
Gara accompanied the video with a transcription of the statement in Basque and Spanish.
"Eta makes it known that as of some months ago it took the decision to no longer employ offensive armed actions," the statement said, suggesting it is ready to pursue a "democratic process," in trying to achieve its goals.
Rodolfo Ares, the regional Basque government's interior minister, said the statement was "totally insufficient".
"The statement is totally insufficient because it does not respond to what the immense majority of Basque people ask and demand from Eta, which is that it definitively give up terrorist activity," Ares told a news conference.
"Eta does not make that declaration so Eta, once again, is making an ambiguous and misleading statement."
However, Ares said even a statement of a temporary halt to attacks was good news.
Eta is seeking an independent Basque homeland in northern Spain and southwestern France.
It is considered a terrorist organisation by the European Union and the United States. It has killed more than 825 people since the late 1960s.
"The political parties and the general public in Spain are treating this with scepticism," Bill Bond, a journalist who has worked in Spain for many years, told Al Jazeera.
"It is the 11th truce declared by Eta since 1981. The ceasefires were broken by Eta because they said the government doesn't promise them enough.
"From the government point of view, when they have sat down and talked to Eta, the group just reiterated their demands for an independent Basque homeland," he said.
The group last announced what it called a "permanent ceasefire" in March 2006, but on December 30 of the same year the organisation set off a powerful car bomb at Madrid's Barajas airport that killed two people.
Since the end of the last ceasefire, police have arrested more than 450 suspected members of Eta or supporters of the group.
It was not clear whether the new truce offer is permanent or whether Eta is signalling it is ready for peace talks with the government of Jose Luis Rodriguez Zapatero, the Spanish prime minister.
There was no immediate response from the Spanish government in Madrid, but the El Pais newspaper, whose editorial line is closely aligned with the ruling Socialist party, said the government had called for "caution".
The newspaper said on its website that Alferdo Perez Rubalcaba, Spain's interior minister, had been in touch with the Basque regional government to assess the statement, especially considering that Eta's statement did not say that the group would give up its weapons.
The group has been weakened by the arrests of several of its key leaders in Spain, France and Portugal, where a bomb-making factory was discovered by police.