Haniyeh was largest obstacle to hostage deal on Hamas side
Israel settles score with arch terrorist after manhunt lasting over 20 years
Killings of Haniyeh and Shukr could increase threats to Israel and US forces
Haniyeh was in Iran for inauguration of newly elected President Pezeshkian
Haniyeh was targeted hours after assassination of Hezbollah's chief of staff in Beirut
Hamas says Netanyahu 'continuing strategy of procrastination and evasion'
Dahlan seen as a potentially neutral leader, with no strong loyalties to either Hamas or Fatah