Former UN chief Kofi Annan is among senior statesmen attending talks in northern Spain which could be a prelude to the dissolution of Eta. The armed Basque separatist group has killed more than 800 people over four decades, but has been weakened by arrests and is observing a ceasefire. Former Irish PM Bertie Ahern and Sinn Fein president Gerry Adams will be at the conference in San Sebastian. They will share their experience of the ending of the Northern Irish conflict. Jonathan Powell, who was closely involved in those negotiations as chief of staff to former British Prime Minister Tony Blair, is also attending the conference. Prisoner call Rumours of a potentially definitive statement have been swirling for several weeks, says the BBC's Sarah Rainsford in Madrid. With international figures flying into the Basque Country for talks, there is an increasing expectation that such a move is imminent, she says. Eta is listed as a terrorist group by Spain, the EU and the US. 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 will be 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." He said the Spanish government must be open to such a move. "It is a two-way street, the whole business of peacemaking," he said. 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 - has 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.