A bomb exploded outside the office of Spain’s governing Socialist Party in Bilbao, the Basque region’s main city, wounding seven police officers after a warning call in the name of the Basque separatist group ETA. The early morning blast badly damaged the party office. The officers were helping to evacuate people and cordon off the zone. The Socialist prime minister, José Luis Rodríguez Zapatero, beginning his second term, appealed last week to opposition conservatives to join him in a united front against ETA.