One fellow hospital director told Sky News: "This is unbelievable and unacceptable. It is a crime."

Muhammad Abu Salmiya, who'd been a constant critical voice on media outlets about the IDF action around Gaza's main hospital, was arrested on Thursday by the Israeli military.

He was part of a convoy moving patients and relatives out of the hospital in the north to the south of Gaza.

Israel-Gaza latest: 'Children killed' in airstrike hours before truce set to begin

The IDF has insisted a Hamas command and control centre was placed beneath the hospital and issued a statement saying: "In the hospital, under his management, there was extensive Hamas terrorist activity.

"Findings of his involvement in terrorist activity will determine whether he will be subject to further questioning."

The Israeli military has filmed its own footage and distributed it to media outlets which it claims shows a tunnel network under the hospital which was used by Hamas.

One fellow Gaza hospital director, Dr Youssef al Akkad, told Sky News from the Gaza European hospital that he knew both Dr Salmiya and the layout of al Shifa hospital well and the claims were baseless.

"All he wants to do is save lives," he said of his fellow doctor.

"Now, he is in the jail… in prison… this is unbelievable and unacceptable and I believe that all the international community should stand against this criminal and shout loudly that this shouldn't happen to the hospital and to the hospital managers and directors. This is a crime."

The bombing of al Shifa and the nearby Indonesian hospital has meant large numbers of patients have been moved to other hospitals in the south.

'Exposed brain infected with worms'

Dr al Akkad said his own hospital alone had overnight received four bus-loads of seriously injured patients and 20 ambulances packed full of wounded.

Pictures he shared with Sky News showed patients being helped down the bus steps including a young boy with both legs broken.

He said he carried some of the patients out including a three-year-old boy with horrific infected head injuries.

"His skull was broken and his brain matter was open and he was alive, can you imagine?" he said.

"We took him down to the emergency and we were trying to clear his wounds and there were worms coming out of his brain matter. We cannot, do not have the medicines to deal with these injuries anymore."

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As we spoke to him by phone, he walked down the stairs from his office and into an emergency room packed with wounded children.

He struggled to hear us over the children's screams as he showed us the scene in the ward using his phone camera.

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"They all have head wounds from collapsed buildings after the strikes," he said.

"They've only just come into the hospital in the last half hour."

He pointed his camera phone to one little girl with a still-bleeding head wound and told us: "She keeps crying for her mother but her mother is seriously ill in the ICU now."

"We are drowning here," he told us. "The situation is very critical now and alarming. We have triple the number of patients that we have the capacity to cope with."

The truce cannot come soon enough for the doctors.

"We are hoping it will allow us time to move some of the more seriously injured through Rafah Crossing and into Egypt," he said, "because otherwise they will die".