The US embassy in Qatar on Monday warned web users about fake social media accounts in the name of its ambassador created "to scam people out of money".
"We have recently been made aware of fake social media accounts claiming to be Ambassador Dana Shell Smith," the embassy said in a press release.
"These accounts purporting to be Ambassador Smith were used in attempts to scam people out of money and are fake."
Smith also took to Twitter to caution her almost 10,000 followers that a fraudulent account on networking site LinkedIn had been created in her name.
Smith, who has been the US ambassador in Doha since July 2014, tweeted: "If you received a job offer from me, it is fake. I don't have a LinkedIn account, & I will never ask you to send money."
In April, the US embassy in Lebanon similarly warned that messages seeking money, purportedly from Ambassador David Hale, were the work of fraudsters.
The scam reportedly involved both emails and use of LinkedIn, with targets being invited to "connect" on the website with Hale.