JERUSALEM—Facebook said Wednesday it has broken up a hacker network used by Palestinian President Mahmoud Abbas’ intelligence service in an attempt to keep tabs on journalists, human rights activists and government critics. The report by the social networking giant threatened to deal another embarrassing blow to Abbas’ Fatah party weeks ahead of parliamentary elections. Fatah, plagued by infighting and public malaise, already appears poised to lose power and influence if the vote takes place next month. In its report, Facebook said that elements linked to the Preventive Security Service “used fake and compromised accounts to create fictitious personas.” Posing as young women, journalists and political activists, they then sought “to build trust with people they targeted and trick them into installing malicious software.” The malware, disguised as chat applications, would give the security agency access to targets’ phones, including contacts, text messages, locations and even keystrokes, Facebook said. It said …