The assassination of Hamas leader Ismail Haniyeh in Tehran has escalated tensions in the Middle East, with Iran and Hamas accusing Israel of the attack. Iranian Supreme Leader Ayatollah Ali Khamenei vowed revenge, calling it a 'bitter and difficult incident' and a provocation designed to escalate conflict. The newly inaugurated Iranian president Masoud Pezeshkian faces internal pressure to respond, while Vice-President Mohammad Reza Aref accused the West of complicity through silence. The assassination, condemned by Russia and other countries, has raised fears of a larger regional conflict. Palestinian regions have declared strikes in mourning, and international leaders, including Australia's Deputy PM, have called for restraint to prevent further escalation.