CAIRO/BEIRUT/DUBAI (Reuters) -The killing of a Hamas chief in Lebanon removes a big name from Israel’s most-wanted list but could drive the Palestinian group's exiled leaders deeper into hiding, hampering efforts to negotiate further Gaza ceasefires and hostage releases. Hamas deputy leader Saleh al-Arouri was struck down by a drone in the southern suburbs of Beirut, the stronghold of Hamas' Iranian-backed Lebanese ally Hezbollah, in an attack widely attributed to Hamas' sworn foe Israel. Israel has not confirmed or denied a role, but the attack came a month after Israeli broadcaster Kan aired a recording of the head of Israel's domestic security agency Shin Bet vowing to hunt down Hamas in Lebanon, Turkey and Qatar even if took years.