Powerful media magnate Rupert Murdoch has apologised after suggesting that Barack Obama was not "a real black president," triggering outrage.
In a message posted to his @rupertmurdoch Twitter account late on Wednesday, the 84-year-old owner of News Corporation had seemed to question Obama's racial identity while comparing him unfavourably to Republican presidential candidate Ben Carson, an African American retired neurosurgeon.
"Ben and Candy Carson terrific. What about a real black President who can properly address the racial divide? And much else," Murdoch tweeted.
The message was retweeted 1400 times and mentioned 1200 times amid an outpouring of anger on the internet.
Murdoch took to Twitter again on Thursday saying: "Apologies! No offence meant. Personally find both men charming."
Race remains a highly sensitive issue in the United States, where a series of police brutality cases against blacks have fuelled protests and debate since the summer of 2014.
Carson, who is polling well in the race for the Republican presidential nomination, weighed in to defend Murdoch, whose media empire includes cable and broadcast television networks and newspapers in several countries.
"I know Rupert Murdoch, he's not a racist by any stretch of the imagination. He's just expressing his opinion. I think it's much ado about nothing," Carson told CNN.
"Everybody is entitled to their opinion. I believe what he was making reference to is the fact here was a man who is a black president that the black community was excited about and who came in and policies have not elevated the black community, has not been beneficial," Carson said.
"There's more unemployment, more poverty and I believe that's what he was really referring to."
Asked once if he believed Obama was "a real black president," Carson replied: "I wouldn't even get into such a conversation."
Asked again, he said: "He's the president and he's black."