Spanish Prime Minister Jose Luis Rodriguez Zapatero has admitted holding high-level talks with the Basque separatist group, Eta.
Zapatero: "Direct and indirect contacts over a short period"
"There have been direct and indirect contacts over a short period," he said, adding he had felt obliged to seek a negotiated end to violence.
However, he added that Eta had made unacceptable political demands.
Mr Zapatero broke off the talks after an Eta car bomb killed two men in a car park at Madrid airport last December.
That attack took place despite the declaration by Eta of a unilateral ceasefire 15 months ago.
The truce was called off earlier this week.
Eta said that from Wednesday it would defend the Basque country "with weapons and on all fronts".
The announcement suggests that another big attack could be imminent, observers say.
The opposition Popular Party says Mr Zapatero's Socialist government has shown weakness by trying to deal with Eta before it renounces violence.
Hitting back, Mr Zapatero said: "I would have wished to have had the backing other prime ministers had."
He said that when he had been in opposition, he had offered then Prime Minister Jose Maria Aznar his full support.
Eta has killed more than 800 people in its four-decade campaign to set up an independent state in northern Spain and south-western France.