By Ali Sawafta JENIN, West Bank (Reuters) -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,

Associated Press journalists saw a handful of tanks move Sunday into Jenin, long a bastion of armed struggle against Israel.

Israeli tanks entered the occupied West Bank as the IDF prepared to fight Palestinian militant groups in the area's refugee camps. The move marks the first time Israel has sent tanks into the occupied West Bank in more than 20 years.

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.

Gaza Hamas says it is delaying further negotiations with Israel until 620 Palestinian detainees, who were supposed to be released on Saturday, are handed over, placing the fragile Gaza ceasefire in jeopardy as violence escalates in the occupied West Bank.

Israel said on Sunday it was scaling up a weeks-long offensive in the occupied West Bank, sending in tanks to a militant stronghold and pledging to keep troops in place for the next year in areas where Palestinians have fled.