New Delhi, July 22 -- DEIR EL-BALAH - Families displaced to the Zeitoun neighborhood have been watching the yellow concrete blocks advance for weeks. By Tuesday, they were 70 meters from the nearest homes, down from a line that was supposed to mark the outer edge of an Israeli security buffer when the ceasefire took effect last October. Seventy-one households have nowhere left to go.

The blocks keep moving. Israel's "yellow line," the system of concrete barriers placed by Israeli engineering units after October's ceasefire as field demarcations of buffer zones, has expanded Israeli control from approximately 53 percent of the Gaza Strip to 64.9 percent, according to Al Jazeera's documentation of the line's advance. In land, Israel's foot...