Israel tightened its closure of the Hamas-controlled Gaza Strip on Friday in response to cross-border rocket fire, preventing even UN humanitarian supplies from getting in, officials said. The Israeli Defence Ministry ordered all of the border crossings with Gaza closed and said only “humanitarian cases” which receive Defence Minister Ehud Barak’s personal approval will be allowed through. “If milk is low in Gaza, the minister will be asked to approve a milk shipment, and it will enter,” a Defence Ministry spokesman said. Gaza is home to 1.5 million people, most of whom depend on foreign aid. Barak had vowed to broaden Israeli military operations against Gaza militants who have fired more than 110 rockets into the Jewish state in the last three days. One of the makeshift rockets landed 40 meters from an Israeli nursery school on Friday, and government spokesman David Baker said Israel “will not be deterred from taking any necessary steps” to halt the fire from Gaza.