Shadia Abu Middin had fled Israel’s war against Hamas twice. Then on Dec. 31, Israel told the 44-year-old mother of four in Gaza to run again, but she didn’t know where to go. 

Palestinians are fleeing into an ever-shrinking section of the Gaza Strip as Israel’s offensive enters its fourth month and its military asks the enclave’s residents to leave more areas it says are unsafe. The Israeli warnings are pushing people to concentrate into just one-third of the strip, the United Nations agency for Palestinian refugees says. In effect, the ground available to its 2.2 million people has shrunk to an area slightly larger than the Bronx.