The US embassy in Serbia has begun pulling out non-essential staff following the storming of the building on Thursday.
One person died and more than 100 were injured in the riots
Around 1,000 protesters set fire to the embassy in Belgrade in protest at Washington's support for Kosovo's declaration of independence.
A convoy of around 40 cars carrying American staff and family members has now left Belgrade.
They are expected to remain abroad for up to 10 days, the US embassy said.
"We are not sufficiently confident that they are safe here," said US Ambassador Cameron Munter.
The embassy also offered private US citizens the chance to join the convoy to Croatia.
Repairs are being carried out to the embassy building, which remains closed.
Repairs are being carried out to the US embassy building
Several other embassies of countries seen by the protesters as supporting Kosovo were also targeted, but they have not announced plans to withdraw staff.
One person was killed and more than 100 injured in the violence, which also saw shops looted.
Serbian media say the authorities have identified a charred body found in the grounds of the American embassy after the riots as that of a young Serb man originally from Kosovo.
He is said to have fled to Serbia after the Nato-led invasion of the territory in 1999.
Police are believed to have arrested 200 people during the riots and the authorities are vowing the bring those responsible to justice.
"We are collecting evidence and are identifying the culprits," said Serbia's senior state prosecutor, Slobodan Radovanovic, in a statement.
US to blame
The situation is calm today, says the BBC's Bethany Bell in Belgrade, but Serb opposition to Kosovo's declaration of independence last Sunday remains as strong as ever.
The minister responsible for Kosovo, Slobodan Samardzic, said the US was to blame for the violence.
"The root of violence is the violation of international law", he said.
"The Serbian government will continue to call on the US to take responsibility for violating international law and taking away a piece of territory from Serbia".
There have been calls in Serbia to boycott the products of those countries, many from the European Union, that recognised Kosovo.
An email campaign suggests closing accounts with some foreign banks.