The United Nations said 20 trucks that had been due to deliver aid to the besieged Gaza Strip via the Rafah crossing from Egypt on Tuesday had not entered the enclave.
"We hope the materials can enter Gaza tomorrow," UN aid spokesperson Eri Kaneko said.
Senior UN aid official Lynn Hastings earlier told the UN Security Council that 20 trucks were due to cross on Tuesday. Since Saturday, 54 trucks have crossed into Gaza carrying food, medicine, and water, which UN Secretary-General Antonio Guterres described as "a drop of aid in an ocean of need."