Tens of thousands of Palestinians streamed into the most heavily destroyed part of the Gaza Strip on Monday as Israel lifted its closure of the north for the first time since the early weeks of the 15-month war with Hamas in accordance with a fragile ceasefire.

Some troops had been expected to withdraw to allow hundreds of thousands of displaced Gazans to go home. But Israel said the hostage exchange before that step had not gone as agreed. Hamas accused Israel of stalling.