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,

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.

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 has stepped up its raids in West Bank towns and cities over the weekend in an apparent response to bus bombings near Tel Aviv last week.

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.