Hamas has released 2 American hostages but many remain unaccounted for. Here's what you should know

Aid workers celebrate after the brief opening of the Rafah Crossing on Saturday. CNN

People on the Egyptian side of the border were jubilant as the Rafah crossing briefly opened on Saturday morning, celebrating with ululations and chants.

The crossing closed quickly after 20 trucks crossed into Gaza, according to a CNN stringer on the Egyptian side of the border.

The 20 aid trucks were from the Egyptian Red Crescent, according to a spokesperson for the United Nations Secretary-General. 

UN aid trucks are expected to move through the border crossing into Gaza on Monday, the UN spokesperson told CNN.