Basque separatist group ETA insisted Tuesday that a cease-fire it declared in March still stands, even as it claimed responsibility for a Dec. 30 car bombing that killed two people in Madrid.

ETA made its assertion in a statement sent to the pro-independence newspaper Gara, which often serves as a mouthpiece for ETA communiques.

ETA said it did not mean to cause casualties in the attack, accusing the government of failing to evacuate the parking garage targeted at Madrid's airport despite three warning calls pointing out exactly where the car bomb was parked. The airport was largely evacuated, but both victims were sleeping in parked cars.

ETA blamed the Spanish government and the governing Socialist party for "placing obstacles endlessly in the democratic process," Gara said in a summary of what it called a long Basque-language statement.

Hours before ETA's statement, the government announced the arrest of two suspected ETA members in southern France linked to arms caches found in late December and last week in the Basque region. They were the first arrests since the Madrid car bombing.

ETA and its political supporters had been warning in recent months that continued arrests and trials of suspected ETA members were endangering the peace process, which was launched with its announcement March 22 of a "permanent" cease-fire. It had been demanding, and the government refusing, the transfer of ETA prisoners from jails around Spain to prisons in the Basque region.

Spain's government has responded to the bombing by scrapping plans for negotiations with ETA and declaring the once-promising peace process terminated.

Interior Minister Alfredo Perez Rubalcaba said he had not immediately read ETA's statement, but his initial impression was that "ETA has only one path left to take, which is to end the violence."

In its statement, ETA reiterated a claim that the government had made, and was not keeping, unspecified promises as part of the process that began with the truce.

The group wants to promote the peace process, but reserves the right to "respond" if what it calls government aggression against the pro-independence movement continues, Gara said.

ETA insisted progress in the peace process must come from a "political agreement" that includes "the minimum democratic rights owed to the Basque country," an apparent allusion to Basques long-standing demands to be able to decide between independence and remaining part of Spain.

It called on the government to halt "police formulas and failed policies that lead nowhere," said Gara, which did not publish a full text of the ETA statement.

The explosion destroyed a five-story parking garage at Madrid airport, which in addition to killing the two Ecuadorean immigrants, injured 26 people.

Until now, ETA had not claimed responsibility for the bombing but a caller warning of the blast said he represented the group.

ETA's political wing, Batasuna, has said it was caught off guard by the explosion, suggesting a rift between the two camps, and on Monday it urged ETA to maintain the cease-fire.

ETA has killed more than 800 people since the 1960s in its quest for an independent Basque homeland.

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