The United Nations said Tuesday that a "forcible transfer of civilians" in the Gaza Strip could be in breach of international law as it warned Israel against any such action.

The U.N. human rights office said a legal temporary evacuation of civilians came with obligations on Israel, which, the Geneva-based agency said, it appears to have made no attempt to fulfill.

Israel has demanded that residents of north Gaza leave for the south, hoping to clear the area of civilians in preparation for a perilous urban ground assault.

"We have grave fears about the toll on civilians in the coming days. Military operations show no signs of abating," U.N. rights office spokeswoman Ravina Shamdasani told a media briefing.

"International law requires that any lawful temporary evacuation by Israel, as the occupying power, of an area on the basis of the security of the population or imperative military reasons must be accompanied by the provision of proper accommodation for all evacuees, undertaken under satisfactory conditions of hygiene, health, safety and nutrition.

"There appears to have been no attempt by Israel to ensure this for the 1.1 million civilians ordered to move."

"We are concerned that this order combined with the imposition of a 'complete siege' on Gaza may not be considered as lawful temporary evacuation and would therefore amount to a forcible transfer of civilians – in breach of international law."

Israel launched a vicious aerial bombardment of the Gaza Strip in response to an incursion by the Palestinian resistance group Hamas on Oct. 7.

Over 2,800 Palestinians, mostly civilians have since been killed in Gaza, while Israel reported a death toll of 1,400.

Israel has also deployed tens of thousands of troops to the border in preparation for a full-scale ground offensive.