US Airways has apologised after an explicit photo was sent from its official Twitter account in response to a customer complaint.

It said in a statement that it was trying to flag the image as inappropriate but instead mistakenly included it in a message.

The tweet was deleted after approximately an hour but not before it had been retweeted hundreds of times.

The airline said it regretted the error and was reviewing its processes.

The image, which featured a naked woman and a toy plane, had originally been sent to the company's Twitter account by another user, it said.

It was then attached to a tweet that was sent to a US Airways customer who had taken to the social network to express her frustration that her flight was delayed.

Once the mistake had been realised US Airways deleted the offending tweet and issued an apology.

"We apologise for an inappropriate image recently shared as a link in one of our responses. We've removed the tweet and are investigating," it said on its Twitter feed.

The company has more than 420,000 followers on its Twitter account and has not tweeted since.

US Airways is merged with American Airlines, who were also caught up in a Twitter controversy on Monday after a 14-year old Dutch girl sent a tweet to the airline implying she was part of al-Qaeda group and planning an attack.

American Airlines responded via Twitter saying that her details would be passed to the FBI for investigation.

Both tweets have now been deleted and the girl's Twitter account has been suspended.

Dutch police said that Twitter had disclosed to them the internet address that the tweet was written from and that they were now questioning a 14-year-old girl.

However, other copycat tweets now appear to be being sent to American Airlines from other teenagers' Twitter accounts, according to the Washington Post.