McDonald's on Friday tendered apology to US President Donald Trump for criticising him in a tweet, saying the account was hacked by an external source.

"You (Trump) are actually a disgusting excuse of a President and we would love to have Barack Obama back, also you have tiny hands," the hacked tweet said.

Though the tweet was deleted quickly after it was posted but before that it got attention of many people and was retweeted by more than 1,000 times.

“Based on our investigation, we have determined that our Twitter account was hacked by an external source,” McDonald's said, adding, “We took swift action to secure it, and we apologise for the tweet as it was sent through our corporate McDonald’s account."