Separatist group ETA has said it will take steps towards peace if Spain stops arrests and so-called “attacks” in the Basque region.
It wants the government to allow separatist parties – outlawed because of their support of ETA – to run in local elections in May.
In March, Madrid said it had smashed an ETA commando unit, arresting eight people and siezing a large quantity of bomb-making materials.
A minister said the unit was suspected of being behind 24 attacks between 2004 and 2006.
The crackdown came after Spain’s prime minister called off peace talks with ETA in December. The group had ended a ceasefire with a car bombing at Madrid’s airport which left two men dead.
At one of Batasuna’s last meetings, its leader Arnaldo Otegi said separatists would be represented in May’s elections. But he did not say how.
Batasuna was outlawed for suspected links to ETA. The Attorney General has called on the ASB party, created by Batasuna to contest the poll, to be banned as well.