US envoy to Qatar to step down in middle of crisis

The US ambassador to Qatar said on Tuesday she was leaving her post in Doha, in the middle of the worst diplomatic crisis involving America's Gulf allies in years.

"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," Dana Shell Smith said on Twitter on Tuesday.

Shell Smith did not say why she was stepping down, if she was staying within the diplomatic service or who would replace her. 

Many US ambassadors leave their posts after serving for about three years. 

Her departure comes with Washington sending mixed signals over the Gulf crisis, which saw Saudi Arabia and several of its allies cut ties with Qatar claiming that Doha supported extremist groups.

Qatar strongly rejects the allegations.

US President Donald Trump has signalled his support for the Saudi-led move but other US officials have been more cautious and called for dialogue to end the crisis. 

Hours after his secretary of state urged Saudi Arabia and its regional allies to ease their blockade imposed on Qatar, Trump on Friday called on the Gulf state to stop funding groups that commit terrorism.

Trump said Qatar has historically financed such groups "at a very high level".

"We had a decision to make, do we take the easy road or do we finally take a hard but necessary action," he said. "We have to stop the funding of terrorism. I decided ... the time had come to call on Qatar to end its funding."

Shell Smith was appointed ambassador to the Gulf kingdom 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." 

She also retweeted a tweet criticising Trump after he criticised Mayor of London Sadiq Khan following the attacks in London in early June which left eight people dead.

Qatar is home to al-Udeid, the largest US airbase in the region, which houses around 10,000 troops.