The tweet read: “@realDonaldTrump You are actually a disgusting excuse of a President and we would love to have @BarackObama back, also you have tiny hands.”
The tweet was posted at 9:16 a.m. ET and was retweeted hundreds of times before it was deleted.
McDonald's spokeswoman Terri Hickey said Thursday night that the company has determined a hack was the culprit. "Based on our investigation, we have determined that our Twitter account was hacked by an external source," she said. "We took swift action to secure it, and we apologize this tweet was sent through our corporate McDonald’s account."
Based on our investigation, we have determined that our Twitter account was hacked by an external source. Read more: https://t.co/X5NwVI5sKp
— McDonald's (@McDonaldsCorp) March 16, 2017
Initially, McDonald's said that the account had been "compromised" and that company officials were looking into the incident.
"Twitter notified us that our account was compromised," Hickey said in a statement to ABC News about an hour after the tweet was posted. "We deleted the tweet, secured our account and are now investigating this."
Twitter would not confirm to ABC News that it had communicated with McDonald's, saying only, "We do not comment on individual accounts for privacy and security reasons."
ABC News' Daniel Linden, Dennis Powell and Rebecca Jarvis contributed to this report.