What Israel is calling "Operation Iron Wall" against Palestinian armed groups has triggered an exodus of around 40,000 people from four camps in the north of the occupied West Bank: Tulkarm, Nur Shams, Jenin and Far'a.

Israel’s military sent tanks into the occupied West Bank for the first time in more than two decades as it expanded operations in the territory on Sunday in a move decried by Palestinian authorities as an escalation of aggression.

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.

Israel says its military operation in occupied West Bank refugee camps is to "prevent the return of residents and the resurgence of terrorism."

A month-long Israeli military operation targeting the four major refugee camps of the northern West Bank - Tulkarem, Nur Shams, Jenin and Al-Fara’a – has prompted a wave of displacement the UN says has not been seen since 1967.

Israeli tanks continue their incursion into the vicinity of the Al-Ghabz area near Jenin camp, West Bank.

Israel is carrying out a military operation in the occupied West Bank and more than 40,000 Palestinians have been forced out of their homes, according to Israeli officials and the United Nations. CBS News' Debora Patta reports.