London – The US ambassador in Qatar announced on Tuesday that she was leaving her post in Doha.

Dana Shell Smith announced on Twitter: “This month, I end my 3 years as US Ambassador to #Qatar. It has been the greatest honor of my life and I’ll miss this great country.”

She did not explain why she was stepping down and did not mention whether she will remain part of the diplomatic mission or who will be appointed in her place.

Several US ambassadors leave their posts after around three years of service.

In Washington, officials said the ambassador had made a personal decision to leave the post earlier this year after serving a normal three-year tour.

“Ambassador Dana Smith’s assignment as ambassador comes to an end this month and she will depart Qatar later this month as part of the normal rotation of career diplomats throughout the world,” a senior State Department official said.

“Her decision to leave the foreign service was made earlier this year. We wish her the best as she moves on from the Department of State.”

Smith was appointed ambassador to the Gulf emirate by Barack Obama in 2014.

Last month she appeared to express dissatisfaction with political events back home in another message posted on social media.

She took to Twitter in the hours after Trump’s dramatic sacking of FBI director James Comey, tweeting: “Increasingly difficult to wake up overseas to news from home, knowing I will spend today explaining our democracy and institutions.”