JERUSALEM — Israeli soldiers opened fire Thursday on a truck attempting to deliver humanitarian aid to the beleaguered Gaza Strip, killing one United Nations-contracted driver and seriously wounding another, U.N. officials said.

The shooting occurred at the Erez checkpoint, the main entrance used by relief agencies to funnel badly needed food and medical supplies into Gaza, where Israel is waging a devastating, 13-day-long military campaign against the militant Islamic group Hamas.

U.N. officials said that they had contracted the truck to deliver supplies into Gaza, and that the Israeli military had approved the delivery. But Israeli ground troops, which control the Erez checkpoint, fired on the truck. It wasn’t clear what caused the Israeli soldiers to open fire, and Israeli military officials weren't immediately available for comment.

Relief officials said that as a result of the …