Professor Michal Pędziwiatr told the BBC: “We saw the shooting attack. And what a surgeon can do in a situation like this?… We decided to help the victims as soon as possible.”

“We rushed into the area where the shooting was and started our rescue, because there were no ambulances available, there were no professionals around.”

Pędziwiatr said his colleague, who has been named by local media as Dr Mateusz Wierdak, used his hand to stem the bleeding from the most severely injured policeman, allowing time for an ambulance to arrive.

On Sunday it was reported that both injured officers had emerged from comas.

Witnesses who were near the Main Market Square have described their panic and confusion as the attack unfolded.

Ruby Catherine Warren, from London, heard gunfire and “yelled at my friends to run and we all sprinted for our lives”.

She said they “just kept sprinting” until they found a hotel to shelter inside.

Tom Brook, from West Yorkshire, was inside a McDonald’s near the square when he heard “multiple gunshots and saw people running for cover”.

“I then walked into the square and saw paramedics working on someone outside [a shop] and there was a dead body covered in foil blankets 20 meters away,” he said.