The Basque separatist group Eta has urged the governments of Spain and France to respond positively to its declaration of a permanent ceasefire.
Reaction has been optimistic but cautious
In its second statement in two days, the armed group called for a peaceful solution to the Basque conflict.
European Union foreign policy chief Javier Solana said he was cautious but acknowledged Eta's announcement was good for Spaniards and Europeans.
Spain's prime minister has warned that any peace talks will be "difficult".
Eta is blamed for killing more than 800 people in its four-decade fight for independence for the Basque region of northern Spain and south-west France.
The BBC's Danny Wood, in Madrid, says most Spaniards have responded positively but cautiously to Wednesday's announcement of Eta's permanent ceasefire.
Eta, which is classed as a terrorist group by the US and the European Union, declared an "indefinite" ceasefire in 1998 but peace talks broke down and the bombing campaign resumed a year later.
The group has never previously called a permanent stop to the violence.
Eta's new statement was published in the Basque daily newspaper Gara.
"It is the moment to speak out," it said.
"All sectors together must make serious commitments so that all together we can construct the democratic solution that Euskal Herria [the Basque region] needs.
"It is the moment to act with courage and take deep decisions, moving from words to action."
Prime Minister Jose Luis Rodriguez Zapatero has said he will take time deciding how to respond to Wednesday's statement.
1959: Eta founded
1968: Eta kills San Sebastian secret police chief Meliton Manzanas, its first victim
1973: PM Luis Carrero Blanco assassinated
1978: Political wing Herri Batasuna formed
1980: 118 people killed in bloodiest year
Sept 1998: Indefinite ceasefire
Nov 1999: End of ceasefire, followed by more bomb attacks in January and February 2000
Dec 2001: EU declares Eta a terrorist organisation
March 2003: Batasuna banned by Supreme Court
May 2003: Two police killed in Eta's last deadly attack
Nov 2005: 56 alleged Eta activists on trial in the largest prosecution of its kind
March 2006: Eta declares permanent ceasefire
"We will react with prudence to reach the end of this historic drama," he said.
But opposition leader Mariano Rajoy said the ceasefire was a pause and it did not amount to a renunciation of criminal activity.
The declaration was also rejected by Spain's Association of Victims of Terrorism as a "new trick by the murderers to achieve their political objectives".
French President Jacques Chirac said Eta's declaration "raises great hopes for Spain and for the fight against terrorism", his office said.
The ceasefire will come into effect on Friday.
Some experts say this could be the beginning of the end of violence in the Basque region.
But there is no roadmap for peace, says our Madrid correspondent.
Eta's activities have been waning, with the number of bombings falling in recent years. The last deadly Eta attack was in May 2003.
Some analysts said Eta's campaign became virtually untenable after the Madrid train bombings in March 2004, blamed on Islamists, caused widespread popular revulsion.
Since 1999, Spanish and French police have also carried out a wave of arrests which are said to have hit the organisation hard.