"SASCOC, like the rest of the public, knows no more than what is in the public domain," the group said. "The organization is in no position to comment on the incident other than to say our deepest sympathy and condolences have been expressed to the families of all concerned."
Pistorius' father, Henke, declined to comment when contacted by the AP, saying only "we all pray for guidance and strength for Oscar and the lady's parents."
Agent Peet van Zyl and coach Ampie Louw couldn't be reached, while Pistorius' cellphone went straight to voicemail.
Former 100-meter world record-holder Asafa Powell tweeted about Steenkamp's death.
"Sad news about (at)oscarpistorius & fatal shooting of his girlfriend he's a true inspiration & amazing athlete. A real tragedy for all," Powell wrote.
Pistorius became an inspiration to many by overcoming his disability to compete at the highest level. Born without fibula bones due to a congenital defect, he had his legs ampuated at 11 months. But he still played sports, including rugby.
"It's incredible for anyone involved with Oscar, especially his family," Former Italian pole vaulter Andrea Giannini, who coached Pistorius from 2009-11, told the AP. "I knew Oscar well. I'm hoping it was just a tragic accident. He's a marvelous person, a really sweet and calm guy. It seemed like this was a calm time for him. He seemed really happy and well-balanced."
AP Sports Writers Stephen Wilson in London, Andrew Dampf in Schladming, Austria, and Gerald Imray in Cape Town, South Africa, and Associated Press writer Daniella Matar in Milan, contributed to this report.