The main United Nations agency aiding Palestinians in Gaza said early Sunday that about 300,000 people had fled over the past week from Rafah, the city in the enclave’s southernmost tip where more than a million displaced Gazans had sought shelter from Israeli bombardments elsewhere over the past seven months.

The U.N. agency, known as UNRWA, made the announcement on social media hours after the Israeli government issued new evacuation orders in Rafah and elsewhere in Gaza, deepening fears that the Israeli military was preparing to invade the city despite international warnings.

The World Food Program echoed those warnings on Sunday, expressing concern about displacement of civilians and saying that a full-scale invasion of Rafah would be “catastrophic.”

“Families are once again on the move, searching for shelter, food, water — but with fewer resources,” it wrote on social media.

Paltel, the Gaza Strip’s largest telecommunications company, said on Sunday that internet service was down in parts of southern Gaza because of Israeli military operations and that crews were working to restore services “as quickly as possible.”

Doctors Without Borders, an aid group whose staff members have been working in Gaza during the war, also said on social media that it had started to refer the last 22 patients at one hospital, the Rafah Indonesian Field Hospital, to other facilities because it could “no longer guarantee their safety.”