A PR executive apologized for posting an offensive tweet last week before boarding a flight to South Africa that made her public enemy No. 1 on social media and cost the communications director her job with InterActive Corp.

"Going to Africa. Hope I don't get AIDS. Just kidding. I'm white!" Justine Sacco tweeted on Friday.

Sacco apologized in a statement yesterday.

"Words cannot express how sorry I am, and how necessary it is for me to apologize to the people of South Africa, who I have offended due to a needless and careless tweet," said Sacco, who was born in South Africa, in a statement to ABC and South African newspaper The Star.

"There is an AIDS crisis taking place in this country, that we read about in America, but do not live with or face on a continuous basis. Unfortunately, it is terribly easy to be cavalier about an epidemic that one has never witnessed firsthand," Sacco added.

"There is no excuse for the hateful statements that have been made and we condemn them unequivocally," an IAC statement said.