MADRID – A Basque separatist group, ETA, surprised the Spanish government yesterday by declaring a “permanent” ceasefire, which could be the first step to ending almost 38 years of violence.

In a video statement, the group said that it aimed to “stimulate a democratic process in the Basque Country and build a new framework in which our rights as a people are recognized.”

The communique did not mention the group disarming or disbanding, though it said: “The end of the conflict, here and now, is possible. That is the hope and will of Eta.”

The government of the Socialist prime minister, Jose Luis Rodriguez Zapatero,said the statement was “good news” and noted that it did not speak of Eta pursuing its goal of independence from Spain. But the official reaction remained wary.

“The government’s position is one of caution and prudence,” Mr. Zapatero told parliament.”A peace process after so many years of terror will be long and difficult.”

Last month Mr. Zapatero said that the end of Eta was near but the announcement still came as a bombshell. The interior minister, Jose Antonio Alonso, was on a flight to Germany when the ceasefire was announced.

A decline in Eta’s support and capability has been clear for some time.

Spanish and French police have arrested many of the group’s leaders, Basque nationalists have been drifting away from violence and Eta has not killed anyone since May 2003. Since the train bombings in Madrid in March 2004, any politically inspired violence has been seen as likely to inspire a backlash against Eta.

In May last year, parliament approved a government-sponsored measure allowing official talks with Eta if the group disarmed.

Opinion polls have shown that about 60% of voters approve such negotiations, but the Socialists’ Eta policy infuriated conservatives, prompting thousands of people to march in Madrid calling for tough police action, not talks.

Critics of the Zapatero administration suggested that the government was holding secret meetings with Eta, a charge that it has denied.

“The government cannot agree to a ceasefire,” the head of the Association of Terrorism Victims, Francisco Jose Alcaraz, told Spanish radio yesterday. “It would be like not arresting a rapist who promised not to rape anymore.”