Prime Minister Benjamin Netanyahu of Israel has ordered the Israeli military to come up with a plan for civilians sheltering in the southern city of Rafah to evacuate, his office said on Friday, clearing the way for an expected offensive into the crowded city.

“Any forceful action in Rafah would require the evacuation of the civilian population from combat zones,” the prime minister’s office said, without saying what area those zones would cover.

Israeli forces bombarded the southern Gaza border city of Rafah with airstrikes, killing multiple civilians, Palestinian media reported on Thursday, a day after Prime Minister Benjamin Netanyahu of Israel said the military was preparing to advance on the area, which is crowded with people who have fled other parts of the Strip.

The strikes heightened fears among the more than a million Palestinians crowded into Rafah, which lies along a closed Egyptian border, as Israel’s army has repeatedly warned that it plans to push further south in its ground invasion in Gaza in what it says is an attempt to defeat Hamas.

The Biden administration said on Thursday that it would not at this point support Israeli plans for a military operation in Rafah, a city in southern Gaza where more than half of the enclave’s total population has sought shelter, and both a White House spokesman and the U.N. secretary general warned of catastrophe should Israel attack.

“Given the circumstances and the conditions there that we see right now, we think a military operation at this time would be a disaster for those people,” a White House spokesman, John Kirby, told reporters.