The U.S.-built pier to bring food to Gaza is facing one of its most serious challenges yet — its humanitarian partner is deciding if it can safely and ethically keep delivering supplies arriving by the U.S. sea route to starving Palestinians.

The United Nations, the player with the widest reach delivering aid within Gaza, has paused its work with the pier after a June 8 operation by Israeli security forces that rescued four Israeli hostages and killed more than 270 Palestinians.

Rushing out a mortally wounded Israeli commando after the raid, Israeli rescuers opted against returning the way they came, across a land border, Rear Admiral Daniel Hagari, an Israeli military spokesman, told reporters. Instead, they sped toward the beach and the site of the U.S. aid hub on Gaza’s coast, he said. An Israeli helicopter touched down near the U.S.-built pier and helped whisk away hostages and the commando, according to the U.S. and Israeli militaries.