gaza palestinian militant group say friday five members kill early week israel blow cross-border tunnel dig militants gaza strip bring death toll strike 12. neither side seem eager seek escalation tunnel blow monday israel point action carry side border islamic jihad group say deny access collapse tunnel unable recover body five members islamic jihad hamas dominant islamist group gaza say early lose two people tunnel collapse swear retaliate hamas accuse israel try undermine reconciliation agreement reach mahmoud abbas president palestinian authority last month israel construct sensor-equipped underground wall along 60-km 36-mile gaza border aim complete 1.1 billion project mid-2019 last gaza war 2014 hamas fighters use dozens tunnel blindside israel superior force threaten civilian communities near frontier counterpoint iron dome anti-missile system largely protect country heartland militant rocket barrage israel unite state call hamas disarm part pact hamas palestinian authority israeli peace efforts abbas collapse 2014 could proceed hamas reject demand death toll strike gaza tunnel week rise 12