Doctors at one of Gaza City's last functioning hospitals say they are overwhelmed with casualties from Israeli strikes and are having to carry out operations in filthy conditions with few or no anaesthetics.

One Australian medic volunteering at al-Shifa hospital told the BBC that every day was a mass casualty event, while another described how a baby had been saved from the body of a pregnant woman who had been killed.

Israeli forces are now just 500m (1,640ft) away from the hospital as they expand their ground offensive to fully occupy Gaza City, which Israel's military calls Hamas's main stronghold.

Witnesses say tanks are advancing into the city centre from the south and north-west.

Israeli air and artillery strikes, attacks by quadcopter drones and detonations of remotely driven vehicles laden with explosives continue to drive tens of thousands of Palestinians from their homes each day.

The Israeli military says it is carrying out the offensive in Gaza City to defeat Hamas and secure the release of the hostages still held by the group after 23 months of war.

Warning: Contains graphic descriptions of injuries

Al-Shifa hospital was once the biggest medical complex in the Gaza Strip. It now lies in ruins, pockmarked by craters, with burned-out wards and bullet holes. Inside, medics are working beyond full stretch. Many of the beds do not even have mattresses, medicines are in short supply, and the casualties are endless.

Dr. Nada Abu Alrub, an emergency specialist from Australia, described the scene as a mass murder, a killing, a torture, a nightmare, detailing the lack of anaesthesia and necessary medical supplies, leading to horrific surgical conditions.

The humanitarian crisis is escalating, with civilians fleeing southwards in large numbers amid advancing Israeli military forces, leaving many trapped and struggling to escape the fighting.

The Palestine Red Crescent Society reported that essential medical services are being severely compromised, and hospitals are unable to accommodate the growing number of casualties.