The Basque separatist group Eta says it has called a "definitive cessation" to its campaign of bombings and shootings.
In a statement provided to the BBC, Eta called on the Spanish and French governments to respond with "a process of direct dialogue".
The declaration, if followed through, would bring an end to Eta's campaign of violence, which has lasted more than 40 years and killed more than 800 people.
The Spanish government has not yet responded to the announcement.
Analysts say it is likely to react with caution, and repeat its call for Eta to disarm and disband.
They say Eta has been badly weakened by a security crackdown in recent years.
The declaration follows a conference this week in the Basque Country, attended by international statesmen including former UN Secretary General Kofi Annan, and protagonists in the Northern Ireland peace process.
They called on Eta to lay down its arms.
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