The Israeli army on Monday ordered tens of thousands of people in the southern Gaza city of Rafah to begin evacuating, signaling that a long-promised ground invasion could be imminent. Hamas and Qatar, a key mediator, have warned that an invasion of Rafah could derail the talks. Israel has described Rafah as the last significant Hamas stronghold after seven months of war, and its leaders have repeatedly said they need to carry out a ground invasion to defeat the Islamic militant group.