The United Nations Human Rights Office has warned that Israel is “sealing off” northern Gaza” and may carry out “massive forced transfers of the civilian population,” which it said would amount to a war crime, CNN reports.

The Israeli army, for more than a week, has been carrying out a major military offensive in the northern part of the Palestinian enclave. It ordered all civilians north of Gaza City to leave and has blocked all food from entering northern Gaza since the beginning of the month, according to the World Food Programme.

The U.N. human rights office said Monday that Israel’s roadblocks are effectively closing off northern Gaza and that the Israeli military has reportedly fired on civilians trying to flee, CNN and others reported.

“In the shadow of escalating hostilities across the Middle East, the Israeli military appears to be completely cutting off Northern Gaza from the rest of the Gaza Strip and waging hostilities with complete disregard for the lives and safety of Palestinian civilians.”

According to CNN, Israel’s operation in northern Gaza bears a striking resemblance to a “surrender or starve” proposal made last month by retired Israeli general Giora Eiland. Known as the “General’s Plan,” it proposed the army order all civilians out of northern Gaza and then besiege any Hamas fighters left behind.

Israel’s cabinet has not fully adopted Eiland’s proposal. But Eiland told CNN last week that while there were differences in what the military was doing in northern Gaza, the government had adopted a version of his plan.

“There are a number of plans that Israel has considered and is implementing as part of the overall strategy for Gaza,” an Israeli official familiar with the matter told CNN.

The military told CNN that “the evacuation of the civilian population from the combat areas in the northern Gaza Strip is taking place in order to protect the uninvolved population.” The military said it was committed to upholding international law.

The UN Human Rights Office said that “the separation of northern Gaza raises further concerns that Israel does not intend to allow civilians to return to their homes, and repeated calls for all Palestinians to leave northern Gaza raise serious concerns about large-scale forced transfer of the civilian population”.

“Forcibly transporting the population of Northern Gaza would amount to a war crime and may amount to other atrocity crimes,” he added.

After a year of evacuation orders followed by repeated Israeli shelling of self-proclaimed “humanitarian zones”, many civilians in northern Gaza are refusing to comply with Israel’s latest demand to move. “Anyone who wants to leave northern Gaza wants death,” Jabalya resident Mohammed Ibrahim told CNN by phone last week.