By Raneen Sawafta and James Mackenzie JENIN, West Bank/JERUSALEM (Reuters) -Israel sent tanks into the occupied West Bank for the first time in more than 20 years on Sunday as it ordered the military to prepare for an "extended stay" to fight Palestinian militant groups in the area's refugee camps.

Israeli tanks have moved into the occupied West Bank for the first time in decades in what Palestinian authorities call a “dangerous escalation.”

Israel’s defense minister, Israel Katz, said that 40,000 Palestinian residents displaced from militant hotbeds would not be allowed to return to their homes.

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.

Israel has ordered its military to prepare for an "extended stay" in parts of the occupied West Bank as it steps up operations against Palestinian militant groups, the Israeli defence minister said on Sunday.

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.

Israel deployed tanks in the West Bank city of Jenin for the first time in two decades. While speaking on the matter, Israel’s Defence Minister Israel Katz said that the operation in West Bank would ’

Tens of thousands of Palestinians have fled home following recent Israeli military operations across the northern West Bank.

Israeli tanks have moved into the occupied West Bank for the first time since 2002, shortly after the defense minister said troops will remain “for the coming year” in parts of the territory and indicated that Palestinians who have fled cannot return.