Israeli tanks moved into the occupied West Bank on Sunday for the first time in decades in what Palestinian authorities called a “dangerous escalation,” after the defense minister said troops will remain in parts of the territory for a year and tens of thousands of Palestinians who have fled cannot return.

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.

The Israeli military is expanding its operations in the occupied West Bank and will remain in some refugee camps for the “coming year,” Defense Minister Israel Katz said Sunday.

Hamas will not hold talks with Israel through mediators on any further steps in the fragile, phased ceasefire agreement unless Palestinian prisoners are released as agreed, group official Basem Naim told Reuters on Sunday.

The six Israelis were the last living captives set to be released in the first phase of the cease-fire. The agreement, strained for weeks, has an uncertain future.