Madrid - The militant Basque separatist group ETA planned to mark the investiture of the new Basque regional government with a car bombing in early May, Spanish media Monday quoted Interior Minister Alfredo Perez Rubalcaba as saying.

Rubalcaba made the comment at a press conference during a visit to London following the arrest of nine ETA suspects, including the group's military leader Jurdan Martitegi, in France and Spain over the week-end.

A document seized from Martitegi indicated that he planned to hand over a van loaded with explosives to an ETA cell in late April, the minister said.

ETA apparently intended to use the car for a bombing that would coincide with the swearing in of Patxi Lopez as Basque regional prime minister following the March 1 elections, Rubalcaba explained.

Lopez, a socialist, will be the region's first prime minister defending its unity with Spain since the Basques were granted a wide autonomy in 1979.

The region had hitherto been governed by moderate Basque nationalists who wanted to weaken its ties to Spain.

ETA has threatened to target the new regional government which it describes as "fascist."

The detention of Martitegi, the fourth ETA leader to be captured in less than a year, was deemed a heavy blow to the weakened separatist group.

ETA, which has killed more than 820 people since 1968, is regarded as a terrorist organization by the European Union and the United States. (dpa)