Israeli tanks were stationed on the edge of Gaza City on Wednesday ahead of a planned ground operation into the enclave’s largest urban area, according to eyewitnesses and satellite imagery.

Amid the military build-up, tens of thousands of Palestinians continued to leave the city, which was estimated to have a total of about one million inhabitants – many of them already displaced multiple times – before Israel announced its plans for a ground incursion.

While the Israeli military announced Tuesday that the ground operation had begun, eyewitnesses and satellite images revealed that tanks had yet to enter the city.

Israel’s new operation comes in defiance of international condemnation and as the United Nations and others have warned that the assault will worsen an already dire humanitarian crisis, with parts of the Gaza officially declared under famine. On Tuesday, an independent UN inquiry concluded for the first time that Israel has committed genocide, which Israel denied.