International negotiators have urged the militant Basque separatist group Eta to lay down its weapons, ending a 40-year campaign of violence.
The call from delegates including ex-UN chief Kofi Annan came at a conference in northern Spain seen as a possible prelude to Eta's dissolution.
Neither the Spanish government nor Eta was officially represented.
Eta has killed more than 800 people since the 70s, but has been weakened by arrests and is observing a ceasefire.
Spanish ministers have called on Eta to seize the opportunity to end the violence.
And the BBC's Madrid correspondent, Sarah Rainsford, says the event was so carefully choreographed that it is expected that Eta will respond.
If Eta bows to the demand, as is increasingly anticipated, it would mark a historic end to its violent campaign for an independent Basque homeland in northern Spain and southwestern France.
Eta is listed as a terrorist group by Spain, the EU and the US.
Key recommendations from the talks were that Eta should make a public declaration of the "definitive cessation of all armed action".
If Eta did so, Spain and France should welcome it and agree to talks dealing exclusively with the consequences of the conflict.
"We have come to the Basque country today because we believe it is time to end, and it is possible to end, the last armed confrontation in Europe," the former Irish Prime Minister Bertie Ahern said after the conference.
Mr Ahern was attending the meeting to share his experiences of the ending of the Northern Irish conflict, as was Gerry Adams - president of Irish nationalist party Sinn Fein.
Former Norwegian PM Gro Harlem Bruntland was also present.
According to a Basque party official, Eta has taken a decision to renounce violence definitively and should announce it this week, the AFP news agency reports.
In January, it declared a permanent ceasefire - but such ceasefires have been broken before.
Spain's government has continued to call on Eta to dissolve for good, and disarm.
Last month, hundreds of Eta prisoners called on militants still at large to end the violence.
Eta's political wing had already committed itself to a peaceful struggle for independence.
The conference in San Sebastian was also attended by local politicians - including the Basque branch of the governing Socialist party - as well as radical Basque nationalists.
Patxi Lopez, the Socialist leader of the Basque regional parliament, urged Eta and its supporters to "to take advantage of this opportunity, to truly take advantage to put a final end to it".
Gerry Adams said: "Today's gathering is a very, very significant step and hopefully we will see a step change in the situation arising from today's initiative."
The Spanish government has refused to engage with Eta, saying it will not negotiate while the group holds arms.
Spain's conservative opposition party, the PP - which is expected to win a general election next month - also refused to attend the conference.
The parties point to Eta's "permanent ceasefire" declared in March 2006, which led to the start of a peace process.
Eta broke the ceasefire nine months later by planting a bomb in a Madrid airport car park which killed two people.