CCOO and UGT, called a general strike which succeeded in paralyzing the country and in forcing González's government to negotiate a partial withdrawal of its economic policies. Concurrently, the opposition People's Alliance (AP) suffered from a profound internal crisis since the 1986 election, which had seen the break up of the People's Coalition and the resignation of party leader Manuel Fraga. His successor, Antonio Hernández Mancha, proved unable to improve AP's electoral fortunes and saw his political credibility decimated after an unsuccessful attempt to bring down Felipe González through a motion of no confidence in March 1987. Hernández Mancha ended up quitting in early 1989, with Fraga returning as a caretaker leader who oversaw the merging of AP with its former allies, the People's Democratic Party (PDP) and the Liberal Party (PL), into the new People's Party (PP). Intending his national leadership as temporary, Fraga appointed a then-unknown President of Castile and León José María Aznar as his successor. The 1986–1989 period saw an increase in the terror activity of the ETA Basque separatist group. This reached its peak with the Hipercor bombing on 19 June 1987, which—with 21 dead and 45 injured—would eventually become the deadliest attack in ETA's history. Other deadly attacks included the Plaza República Dominicana bombing on 14 July 1986, three weeks after the previous general election and one day before the newly elected Cortes re-assembled, which left 12 dead and 32 injured; and the 1987 Zaragoza Barracks bombing, with 11 dead—including 5 children—and 88 injured. Concurrently, the PSOE government introduced a policy of dispersion of imprisoned terrorists throughout the entire Spanish territory in order to restrict contacts between them and prevent terrorist organizations from organizing themselves from prison. Political parties signed several anti-terrorist agreements, such as the Ajuria Enea Pact or the Madrid Agreement on Terrorism, aimed at increasing inter-party cooperation on the issue. In January 1989, ETA declared a ceasefire in order to start negotiation talks in Algiers with the Socialist government, but no successful conclusion was reached and ETA resumed its violence campaign. The opposition had pressed for a snap election since the general strike in December 1988. It was not until the PSOE success in the 1989 European Parliament election, the end of the Spanish rotational Presidency of the Council of the European Union in June and the need for tough economic measures before the end of the year that Felipe González