Madrid (CNN) -- The Basque separatist group ETA announced Thursday a "definitive cessation of its armed activity" in a statement published on the website of Gara, a newspaper that the group has used to convey messages in the past.
Listed as a terrorist organization by Spain, the United States and the European Union, ETA is blamed for hundreds of deaths in its decades-long fight for an independent Basque state that it wants carved out of sections of northern Spain and southwestern France.
Thursday's announcement follows a recent push for the group to abandon violence permanently. That effort was led by international figures who include Sinn Fein leader Gerry Adams of Northern Ireland and former U.N. Secretary-General Kofi Annan.
In a nationally televised address hours after the announcement was posted, Prime Minister Jose Luis Rodriguez Zapatero termed ETA's announcement as being of "transcendental importance" and a "victory for democracy."
"Ours will be a democracy without terrorism, but not without memory," Zapatero said, referring to 829 people killed by ETA and their families.
The prime minister praised Spanish police, Civil Guard personnel, the intelligence agency and judicial authorities "who have contributed to this end." Zapatero also singled out France -- which has traditionally been used as a rearguard base for ETA -- and its president, Nicolas Sarkozy, for their assistance.
The prime minister said that it would be up to Spain's next government -- which will be formed after parliamentary elections on November 20 -- to lead the peace process.
Zapatero, whose popular standing has soured amid Spain's deep economic crisis, is not running for a third term. Soon after he was first elected, in 2004, the police intensified their crackdown on ETA as the group's popularity among some segments of Basque society began to wane.
In its own statement Thursday, ETA called of "enormous significance" a one-day meeting held Monday in which Adams, Annan and other leaders met in San Sebastian, a principal Basque city, and called for peace.
After that conference -- which did not include representatives from the Spanish government, the Basque regional government or the main opposition party in Spain, the Popular Party -- former Irish Prime Minister Bertie Ahern read a statement calling for ETA to issue a declaration akin to what it made on Thursday.
The leaders also called on the Spanish and French governments to welcome it and "agree to talks exclusively to deal with the consequences of the conflict."
European Commission President Jose Manuel Barroso hailed ETA's move Friday as "a truly historic moment which ends years of terror and attacks on Spanish society."
The development "marks the culmination of years of unceasing efforts in the fight against terrorism," he said, as he congratulated Spain on its efforts to combat ETA.
Police have cracked down in recent years on ETA in Spain and France, leaving it operationally weak.
There have been numerous statements from the Basque group calling for talks or a peace process of some sort, but all falling short of declaring a definitive end to violence.
The Spanish government has said that since ETA has broken cease-fires in the past, only an authoritative statement that it is putting down its arms for good will do.
In its statement Thursday, the group outlined why now was the right time to make such a declaration.
"A new political time is emerging in the Basque Country," ETA said. "We have a historic opportunity to find a just and democratic solution for the centuries-old political conflict."
The group then added that "dialogue and agreement" should predominate "over violence and repression."
ETA urged the Spanish and French governments to conduct "direct dialogue" aimed at addressing outstanding issues, while calling upon fellow Basques to commit to such a process.
In remarks Thursday night at their respective political party headquarters in Madrid, the two main contenders to replace Zapatero cheered the development but did not detail what they would do next if they were to become prime minister.
Alfredo Perez Rubalcaba, the candidate from Zapatero's Socialist Party who until recently as Spain's interior minister led the fight against ETA, said the announcement "puts an end to decades of broken lives." He called unity among Spanish parties and leaders the "key to this victory," and urged that this unified stance continue.
"Today, the ETA is not the protagonist, because the state of law has won," Rubalcaba said.
Soon after, Mariano Rajoy -- who opinion polls show holds a commanding lead heading into next month's elections -- said that members of his conservative Popular Party take "satisfaction" from ETA's decision, which he insisted was not spurred by any political concessions.
Rajoy called the announcement "an important step," while adding that Spain would rest fully "only when there is the definitive dissolution" of ETA.
Angeles Pedraza, the president of the Association of Victims of Terrorism, offered a similar stance in stating that her group will be satisfied only when ETA "turns in its guns and disbands." This sentiment was echoed by the leader of the moderate Basque Nationalist Party, Inigo Urkullu, who likewise called on the group to "disarm and disband."