The Pentagon’s highly anticipated plan to deliver aid to suffering Palestinians via a floating pier off the Gaza Strip has encountered almost immediate logistical and security setbacks, officials said Tuesday, marking an inauspicious start to the mission intended to ease a severe humanitarian crisis there.

After desperate people seized food destined for a United Nations warehouse over the weekend, U.S., Israeli and aid officials have begun discussing alternative routes into Gaza, said Maj. Gen. Patrick Ryder, the Pentagon’s spokesman.