Israeli troops push deeper into Gaza City amid the most intense bombardment of the war in Gaza. Thousands are fleeing the area the Israelis have now labeled a "dangerous combat zone." Others remain trapped because they have nowhere to go and no means to leave. Survivors describe harrowing scenes of destruction and loss. The United Nations condemns the destruction as "horrendous," with Gaza's infrastructure in ruins. Israel says its campaign will last months, despite global calls to halt the offensive.