Israeli bulldozers have demolished large areas of the now virtually empty Jenin refugee camp and appear to be carving wide roadways through its once-crowded warren of alleyways, echoing tactics already employed in Gaza as troops prepare for a long-term stay.

A month-long sweep for Palestinian militants in the northern West Bank could continue for a year, Israel’s defense minister said, adding that residents who fled will be barred from returning and that a contested UN relief agency’s work there will be halted.