The aid lifeline for Umm Muhammad and hundreds of thousands of other Palestinians is now under existential threat as Israel lays siege to Gaza once again.

President Trump is vowing there will be "hell to pay" if Hamas doesn't release the remaining hostages. Israel is applying pressure as well by blocking aid convoys of food and medical supplies from entering the war-torn strip to force an extension of the first phase of the ceasefire deal.

After more than 16 months of war, Gaza’s population is entirely dependent on trucked-in food and other aid. Most are displaced from their homes, and many need shelter. Fuel is needed to keep hospitals,

The food aid is what’s keeping us alive,” one Gaza resident says. As Israel halts aid going into the enclave, CNN’s Jeremy Diamond explores the impact on people who rely on this lifeline for survival.