GAZA CITY - Israel on Saturday hit parts of Gaza including Rafah where it expanded an evacuation order, as the UN warned an outright invasion of the crowded city risked an "epic" disaster.
AFP journalists, medics and witnesses reported strikes across the coastal territory, where the UN says humanitarian relief is blocked after Israeli troops defied international opposition and entered eastern Rafah this week.
That effectively shut a key aid crossing and suspending traffic through another.
At least 21 people were killed during strikes in central Gaza and taken to Al-Aqsa Martyrs Hospital in Deir al-Balah city, a hospital statement said.
In Rafah, witnesses reported intense air strikes near the crossing with Egypt, and AFP images showed smoke rising over the city.
Other strikes occurred in north Gaza, witnesses said.
Hamas on Saturday accused Israel of "expanding the incursion into Rafah to include new areas in the centre and the west of the city".
Israeli troops on Tuesday seized and closed the Palestinian side of the Rafah crossing -- through which all fuel passes into Gaza -- after ordering residents of eastern Rafah to evacuate.
The army said Saturday troops were fighting "armed terrorists" at the crossing and had found "numerous underground tunnel shafts".
The new evacuation order for eastern Rafah, posted on X by Israeli military spokesman Avichay Adraee, said the designated areas had "witnessed Hamas terrorist activities in recent days and weeks".
Military spokesman Daniel Hagari later said "we have eliminated dozens of terrorists in eastern Rafah".
Israel on Saturday said 300,000 people had fled Rafah since an initial evacuation order, as more residents piled water tanks, mattresses and other belongings onto vehicles and prepared to flee again.