President Trump's Twitter account may be popular among his fans at home, but his latest missives are complicating the work of American diplomats overseas. As some diplomats push back, State Department spokeswoman Heather Nauert cautions that they "are expected to use their judgment."

Consider Trump's personal attack on London's mayor, Sadiq Khan, after Saturday night's deadly terrorist attack in the British capital.

"At least 7 dead and 48 wounded in terror attack and Mayor of London says there is 'no reason to be alarmed!' " Trump tweeted (ignoring the fact that Khan was advising Londoners not to be alarmed by an increased police presence in the British capital).

The U.S. Embassy in London, in contrast, praised the "strong leadership" of the mayor "as he leads the city forward after this heinous attack" in a tweet signed by acting Ambassador Lew Lukens.

At her first State Department briefing, held Tuesday, Nauert played down the contradictions.

Diplomats serving overseas are "professionals," she said, who are "entitled to use social media."

"We expect them to use it responsibly," she said, adding that the U.S. stands "shoulder to shoulder" with the British government in the wake of the London attack.

The U.S. ambassador to Qatar is also on the spot this week after Trump linked Qatar on Twitter with the " funding of Radical Ideology" and seemingly took sides with Saudi Arabia in Monday's diplomatic flare-up with Qatar.

Trump's Tuesday tweet came a day after Ambassador Dana Shell Smith retweeted some of her previous statements praising Qatar's efforts in combating terrorism financing and its role in countering ISIS.

Nauert echoed that message Tuesday, saying Qatar has made "great progress" in cutting terrorism financing, but warned, "They still have work to do."

Asked whether Trump's tweets signal a shift away from Qatar and toward Saudi Arabia, Nauert stressed, "Our relationship with Qatar is one that is strong."

Qatar is home to the U.S. Central Command's regional headquarters and hosts a key air base for the U.S.-led coalition against ISIS.

Many of the questions at Nauert's debut on the State Department podium were about Trump's tweets. Nauert said Secretary of State Rex Tillerson has no intention of advising the president how to communicate.

She also fielded questions on the department's most recent high-profile departure.

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