"The state has embarked on a strategy to rely on unsubstantiated allegations," he said, citing a neighbor's testimony that an argument had been heard in his home.
According to Pistorius' statement, other neighbors living nearby said they had not heard any argument. He also cited evidence provided by police detective Hilton Botha as "false in material respects."
In the courtroom, Pistorius was seated near Steenkamp's mother, June. She was quoted in the Pretoria News, which published an interview she gave to a British newspaper, saying that she wants to see Pistorius.
"I want to look at Oscar, really look him in the eyes, and see for myself the truth about what he did to Reeva," said June Steenkamp, 67. "Whatever the court decides at the end of his trial, I will be ready to forgive him ... But first I want to force him to look at me, Reeva's mother, and see the pain and anguish he has inflicted on me. I feel I need that."
Reeva Steenkamp was a glamorous model and budding reality TV show star when she was cut down at age 29.
Earlier, a drone carrying cameras flew over the entrance to the courthouse in gray, drizzly skies. Several broadcasters massed live broadcast satellite trucks around the courthouse. A 24-hour cable channel devoted to covering the trial was launched in South Africa on Sunday.
If convicted on the murder charge, Pistorius could be sent to prison for at least 25 years before the chance of parole, the minimum time someone must serve if given a life sentence in South Africa. South Africa does not have the death penalty.
A lesser sentence is possible if Pistorius is found guilty of murder but without premeditation. He also could be convicted of culpable homicide, South Africa's version of manslaughter in which someone is killed through negligence.
The additional firearms charges relate to him allegedly shooting out of the sunroof of a car in one incident and another when he allegedly fired a gun inside a restaurant, apparently by mistake. Ammunition also was found at his house after the shooting that he allegedly did not have proper licensing for.
Judge Thokozile Masipa, hearing the biggest trial of her career, will ultimately pronounce the champion runner innocent or guilty and will decide on any sentence. South Africa has no trial by jury.
Parts of the trial will be broadcast on live television, both in South Africa and across the world. A South African cable channel has been launched which will provide 24-hour coverage of the Pistorius trial, using commentators and prepared feature stories when the court is not in session.
