Oscar Pistorius has broken down in court after the prosecuting barrister demanded he look at a grisly picture of his girlfriend's wounded head in court. Pistorius raised his voice and refused to look at the picture after barrister Gerrie Nel said Reeva Steenkamp's head had "exploded like a watermelon".

As Pistorius sobbed in the dock, Mr. Nel referred to a video showing Pistorius shooting and hitting a watermelon on a firing range.

"You know that the same happened to Reeva's head - it exploded," Mr. Nel said.

As the picture was shown in court, the barrister continued "Have a look. I know you don't want to because you don't want to take responsibility. Take a look".

Appearing to lose his composure, Pistorius replied "I will not look at a picture. I touched her head that night. I know how it felt. I am taking responsibility, by standing here today - I am not looking at that picture".

The photograph showed a side view of Miss Steenkamp's bloodied head, with her eyes closed.

Mr. Nel said "It's time that you look at it".

The judge eventually asked for the picture to be taken down and ruled that the line of questioning was inappropriate, as Pistorius was forced to take a break.

Earlier, Pistorius shook in the dock as Mr. Nel went for the jugular, asking "You killed Reeva Steenkamp, didn't you?" Pistorius said "I did, I made a terrible mistake".

Mr. Nel replied: "Won't you take responsibility? Take responsibility - say 'I shot and killed Reeva Steenkamp".

"She was struggling to breathe"

Pistorius began today's evidence by describing how he carried the model down the stairs of his home after finding her slumped on the toilet.

"She was sitting with her weight on top of the toilet bowl. I checked to see if she was breathing and she wasn't" he told the court.

"I pulled her weight on to me and I sat there crying for some time. I felt her head on my shoulder and I could feel the blood running down me. I thought I felt her breathing. I could see her arm was broken".

"I was trying to pick Reeva up. I could see she was still breathing. She was struggling to breathe".

Pistorius said that he rang 911 and also security - but did not remember either call clearly.

"After I got off the phone with 911, I ran downstairs to open the front door. I could barely pick Reeva up. I opened the front door" he said.

"I ran back up to my room. I went back to the bathroom and tried to pick up Reeva. I got to the second flight of stairs. I was shouting and screaming for help in getting her to the hospital".

Pistorius said he was told to put Ms. Steenkamp down as neighbours said an ambulance was on its way.

"I just sat there and waited for the ambulance to arrive," he said. "I had my fingers in her mouth to help her breathe. I had my hand on her hip to try and stop the bleeding. Reeva had already died when I was holding her so I knew there was nothing the ambulance could do".

"Then the paramedic came to me and said she would like to inform me that Reeva had passed. The paramedic asked me if there was some form of ID. I went to get Reeva's handbag".

Pistorius said that police officers then arrived and checked the house to see if anyone else was there.

"I asked the policeman if I could wash my hands because the smell of the blood was making me throw up. I washed my hands and face" he said.

"I hit the door with all my might"

The athlete was later taken to the police station and arrested over the death. Afterwards he was taken to hospital where doctors conducted tests on him.

In dramatic scenes in court, Pistorius then demonstrated how he tried to break down the toilet door with a cricket bat "using his entire body".

Swinging the bat, he said "I hit the door with all my might".

Asked by his barrister whether he intended to kill his girlfriend, Pistorius responded "I did not intend to kill Reeva or anyone else for that matter".

Yesterday, Pistorius wept uncontrollably in the dock as he described shooting Steenkamp, claiming he thought she was an intruder.

Pistorius denies premeditated murder and illegally possessing ammunition and two further counts related to shooting a gun in public in separate incidents prior to the killing.