Hundreds of U.S. troops are now en route to the Gaza coast to build a massive floating pier off the war-torn enclave that will open up a desperately needed route for humanitarian aid promised by President Joe Biden.
The deployment order, delivered to the troops shortly before Biden announced the effort in his State of the Union address last Thursday, comes five months after the start of the war in Gaza and as Israel has blocked aid trucks from entering, citing security concerns.
International aid organizations say several children have already died of starvation.
MORE: Biden announces 'emergency' US military mission to build pier off Gaza coast to deliver aidTroops and their families who spoke with ABC News said they had been watching the war unfold on social media and elsewhere, but that last week's deployment order came as a shock.
Several troops said telling their kids they were leaving on short notice was the toughest part.
ABC News spoke with troops and their families in Newport News, Virginia.
"We told them that we're going to provide humanitarian aid for people that are in need. And that we're going across the ocean. We'll be back as soon as we're done," said Chief Warrant Officer Three Jason West on what he told his three children, ages 15, 9 and 6.
West is among some 500 Army soldiers who deployed Tuesday from Virginia to the Gaza coast, where they will join Marines and Navy sailors in constructing the floating pier.
Officials describe the pier as a kind of massive floating parking lot that will attach to an 1,800-foot walkway that will attach to shore. It will take at least 60 days before it's up and running. But once built, the pier should enable deliveries of some 2 million meals a day.
The military hasn't built this kind of pier -- a system called JLOTs -- since 2010 when the Army deployed one off of Haiti. The system also was part of a military training exercise in Australia last year.
Biden has promised no U.S. boots on the ground, and officials say they will be working with Israeli forces and other partners in the region to secure the pier's causeway to the shore, as well as offload and distribute the aid packages.
U.S. troops are expected to remain on ships throughout their deployment, which does not have an end date.
"It's indefinite until we're done providing humanitarian aid," West said.