Hamas leader Ismail Haniyeh was assassinated in Tehran, Iran, leading to his funeral in Qatar attended by senior Hamas officials and Qatar's Emir Sheikh Tamim bin Hamad al-Thani. Both Iran and Hamas have blamed Israel for the assassination and have vowed retaliation, although Israel has not claimed responsibility. US President Joe Biden expressed concerns that Haniyeh's killing complicates ceasefire negotiations in Gaza and has urged de-escalation. The assassination, alongside other targeted killings of senior figures in Hamas and Hezbollah, has heightened fears of a broader regional conflict. Biden reaffirmed US support for Israel's defense and highlighted the importance of ongoing efforts to deescalate tensions. Iranian leaders have also condemned the attack, with Supreme Leader Ali Khamenei calling for revenge against Israel.