"Exercise caution if unexpectedly in the vicinity of large gatherings that may become violent", the embassy said in a list of advised actions, asking Americans to "keep a low profile" and "be aware of your surroundings".
She says they have "turned a blind eye" to the situation.
Mr Smyth, who is originally from Ireland, said Trump fans had been given a bad rap, and there had been lots of support for the pub's temporary renaming.
Mr Trump's planned visit has been met with plenty of anger, with 50,000 protesters expected to take to the streets of central London on Friday.
Kim Jong-un blows off Mike Pompeo to look at potato farm
What happened was the Trump administration is divided on its approach toward the procedures of denuclearization. Hua insisted that China hopes to see North Korea and the United States expand their ties and work together.
It is widely believed that such a schedule has been designed for Donald Trump because of the overwhelming protests that are expected to descend on London during his visit.
The two "Beasts" are among and huge motorcade of vehicles flown into Britain on two United States Air Force Boeing C-17 transport planes ahead of Trump's visit.
Last month, Labour member of Parliament Gavin Shuker ran down a list of objections to Trump: the separation of migrant families and detention of children; the US departure from the United Nations' Human Rights Council; the USA president's praise for North Korean leader Kim Jong Un.
Besides protests, United Kingdom supporters of President Trump are also scheduled to hold Pro-Trump rally outside the US Embassy in London. A baby-shaped Trump balloon is expected to fly over Parliament on Friday morning.
They each have 4,000 square feet of floor space, including a Presidential suite with a large office and conference room, a medical suite that can be used as an operating room and two kitchen areas that can feed 100 people at a time.
Trump says US commitment to NATO remains strong despite criticism
Trump did not specify which countries had committed to what, and it remained unclear whether any had changed their plans. NATO Secretary General Jens Stoltenberg , Poland's President Andrzej Duda, Greek Prime Minister Alexis Tsipras, U.S.
She added: 'So there's a very serious message behind this but what we're hoping is that on Friday this can be a symbol that people, no matter what they're campaigning on, can get behind, and can feel that this is representing them and all their campaign issues'.
Mr. Trump has been quick to criticize British society, telling an NRA convention in May that the British didn't have guns but had so much knife crime that one hospital was like a military war zone with its floors awash with blood - a statement quickly rebutted by British physicians and politicians.
"Melania has seen photos of the Trump baby blimp, and she doesn't find it amusing in the slightest, she thinks it's mortifying", a source close to the first lady tells HollywoodLife EXCLUSIVELY.
He will spend just one night in the capital before going to Prime Minister Theresa May's country retreat Chequers in Buckinghamshire.
Prince Harry gets a chuckle out of fan's baby-making remark
The couple walked past the ecstatic royal fans standing five deep against crash barriers, greeting as many of them as they could. Traditionally, members of the royal family are supposed to refrain from showing any political views and are not allowed to vote.