"All it was is a retweet. It wasn't from me, and it did -- it came out of a radio show and other places," Trump said in an interview with Fox News host Bill O'Reilly.
Pressed further, Trump said: "This was a retweet, and it came from sources that weren't very credible, what can I tell you."
And he defended his use of Twitter, saying he likes the medium "because I can get also my point of view out there, and my point of view is very important to a lot of people that are looking at me."
Trump on Sunday stirred controversy by retweeting an image that attributed the vast majority of homicides to blacks.
Trump's @realDonaldTrump Twitter account highlighted a photograph featuring a dark-skinned man wearing a bandana, a dark shirt and military-style pants and holding a handgun sideways and claiming to list "USA CRIME STATISTICS - 2015."
It includes six lines. Two of them: "BLACKS KILLED BY POLICE ~~ 1%" and "BLACKS KILLED BY BLACKS ~~ 97%." The tweet also said blacks are responsible for 81% of homicides in which the victims are white.
Those numbers are fake, and the source the photo cites -- "Crime Statistics Bureau - San Francisco" -- does not exist.
Most blacks are killed by blacks, and most whites are killed by whites -- largely because Justice Department statistics show that homicide victims usually know their killer, and in many cases are related to that person.
The picture also overstates the number of homicides committed by blacks.
According to FBI statistics, of the 2,451 homicides of black people in 2014, 90% were committed by black people, while 8% of the offenders were white.
Of the 3,021 homicides of white people in 2014, 82% were committed by white people, while 15% of the offenders were black. The figures Trump retweeted inaccurately stated that 81% of white homicide victims are killed by blacks.
The Justice Department maintains a Bureau of Justice Statistics, though its figures don't match those Trump retweeted. The FBI's uniform crime statistics lag by a year -- with 2014 numbers only recently becoming available -- and no federal government agency has produced such figures for 2015.
The retweet came two days after a half-dozen white attendees at a Trump rally shoved, tackled, punched and kicked a black protester who disrupted the business mogul's speech.
"Maybe he should have been roughed up because it was absolutely disgusting what he was doing," Trump said Sunday morning on Fox News, less than 24 hours after his campaign said it "does not condone" the physical altercation.