At least 15 Palestinian children died from dehydration and malnutrition at the Kamal Adwan Hospital in the northern Gaza Strip as Israel tightened a crippling blockade on the area, according to local health authorities.

“There are likely more children fighting for their lives somewhere in one of Gaza’s few remaining hospitals, and likely even more children in the north unable to obtain care at all,” Adele Khodr, UNICEF regional director for the Middle East and North Africa, said in a statement.