BBC
A Welsh surgeon who saved lives during the conflict in Syria has described the "evil" of those who bomb hospitals.
David Nott was delivering the BBC's annual Patrick Hannan Lecture at the Hay Festival in Powys.
Mr Nott told the audience how perpetrators claimed the bombings to be "justifiable and intentional".
"Hospitals must be protected and respected. To bomb and destroy hospitals is not just sinful, it is evil," he said.
Mr Nott, born in Carmarthen, has operated in war zones since volunteering to help in a hospital in Sarajevo during the Bosnian conflict.
"In Syria alone there were 454 attacks on hospitals in the last six years, 91% perpetrated by the Syrian and Russian governments. In April 2017 alone there were 25 attacks on medical facilities - that's one every 29 hours.
"Evil is not just performing these acts, it is also denying that they are occurring."
Mr Nott said he had witnessed helicopters dropping barrel bombs on Aleppo's civilian population in 2014, only for President Assad to deny the existence of the weapons in a BBC interview shortly afterwards.
He added modern technology allowed local Syrian surgeons to operate under instruction from London.
Mr Nott used a Skype connection from his office in London to assist with a procedure to create a new jaw for an injured patient on the operating table in Aleppo.
"We were able to break the siege of Aleppo by electronic means and communicate with each other both visually and verbally, and extend that arm of friendship and trust," he said.
But a few days later, he said, the hospital was bombed.
"It was attacked four times in three days, and finally was totally destroyed by a bunker-busting bomb dropped onto the main operating theatre. Maybe the Skype coordinates from my office in London to their operating theatre were intercepted? I will never know."