London(CNN) The US embassy has taken the unusual step of issuing a warning to American citizens in the UK to "keep a low profile" during the visit of President Donald Trump.

There are fears that demonstrations over Trump's three-day visit to the UK, where he will meet with British Prime Minister Theresa May and Queen Elizabeth, could turn violent.

The largest demonstration is expected in central London on Friday where a giant "Trump baby" balloon will fly close to Parliament after being given the go-ahead by Mayor of London Sadiq Khan.

A six-meter "Trump baby" balloon will fly at the London protest.

A statement on the US embassy website warns US citizens to "be aware of your surroundings [and] exercise caution if unexpectedly in the vicinity of large gatherings that may become violent."

As well as in London, protests are expected to take place in Bristol, Newcastle, Leeds, Cambridge and Cardiff after Trump arrives on Thursday.

A small demonstration is expected to take place near Blenheim Palace in Oxfordshire on Thursday, the venue for Trump's black-tie dinner with May on Thursday evening.

There are also plans for protestors to gather close to the US ambassador's residence in Regent's Park, where Trump and his wife, Melania, will stay overnight on Thursday.

On Friday, demonstrators are expected to gather near Chequers, the Prime Minister's country residence, where May and Trump will hold a working lunch.

The biggest protest will take place in central London on Friday when thousands are expected to take to the streets to join the "Stop Trump" march.