MADRID, July 10, 2008 (AFP) - The Basque separatist group ETA observed a ceasefire for nearly one month while the regional Basque parliament debated a plan for a referendum on self-determination, a Spanish newspaper reported Thursday.

Top-selling daily El Pais, citing Basque nationalist sources, indirectly assured Basque regional premier Juan Jose Ibarretxe, a moderate nationalist, that it would not carry out any attacks during the parliamentary debate.

The debate ended on June 27 with the approval by the assembly of Ibarretxe's plan to hold a non-binding referendum on the region's right to self-determination, defying Spain's central government which has vowed to block the plan in court.

The last ETA attack before the start of the parliamentary debate occurred on June 8 when an explosion rocked the printing press near Bilbao of El Correo, the main newspaper in the Basque region.

ETA struck the next time on July 4 with a small blast at a telecoms relay station in the Basque town of Barrundia.

Both attacks caused material damages but no injuries.

ETA is blamed for over 800 deaths in Spain in its 40-year campaign for Basque independence.

It declared a unilateral ceasefire in March 2006, raising hopes for an end to the violence. But an ETA bombing at Madrid's airport in December 2006 that killed two men put an end to tentative peace talks with the government.

ETA officially terminated the ceasefire in June last year, and since then the government has blamed it for four killings.