Mr Biden can expect a warm welcome in Bosnia and Kosovo, analysts say
US Vice-President Joe Biden has arrived in the Balkans for a tour during which he will become the highest-level US politician to visit Serbia in 29 years.
Mr Biden landed in Sarajevo and will spend Tuesday in Bosnia-Hercegovina before going to Serbia and Kosovo.
Officials said he hoped to demonstrate President Barack Obama's commitment to engage with the Balkans and would try to seek to rebuild ties with Belgrade.
The US recognises the independence of Kosovo, something which Serbia rejects.
On the first stage of his three-day tour, Mr Biden is scheduled to meet Bosnia's three-person presidency, address parliament, and meet separately with the representatives of two of the country's rival ethnic groups, Bosniak (Bosnian Muslim) leader Haris Silajdzic and Serb leader Milorad Dodik.
He will be accompanied by the EU's foreign police chief, Javier Solana.
Last week, the US ambassador said the Obama administration wanted to bring "a new focus, a new sense of energy, a new activism with regard to Bosnia-Hercegovina and the region as a whole".
On Wednesday, the vice-president will fly to Serbia, before wrapping up his trip in Kosovo on Thursday. Mr Biden will be the highest-level US official to visit Serbia since President Jimmy Carter toured Yugoslavia in 1980.
The BBC's Helen Fawkes in Belgrade says Mr Biden's visit is being seen by many here as an important signal that the Balkans will not be ignored by the new US administration.
The region has not been high on the foreign policy agenda since the election of President Obama, our correspondent says.
The US recognises the independence of Kosovo, something which Serbs reject
A US official said that Mr Biden's visit would reaffirm support for the integration of the Balkans into the European Union and the Nato.
The vice-president can expect a warm welcome in Kosovo and Bosnia, but he is not a popular figure in Serbia as he strongly backed Kosovo's independence, our correspondent adds.
Serbian political commentator Ljiljana Smilovic told the BBC that he would get a mixed reception from the government in Belgrade.
"The opposition will be impressed, even the anti-American public is going to be impressed," she said.
"But at the same time, it carries a slight risk for the government because it will be seen as being too cosy with someone who is really perceived as an enemy of the Serbs."
Our correspondent says that for the Serbian government, Kosovo remains the biggest obstacle in dealing with the US.
But earlier this year, President Boris Tadic said he wanted to open a new chapter with Washington because good relations would ensure stability in the region.