KIEV (Reuters) - U.S. President Donald Trump’s national security adviser John Bolton said on Friday that Washington would not weigh in on an idea to swap territory between Serbia and Kosovo.

Belgrade has raised the idea of settling a dispute that has hindered both Serbia’s and Kosovo’s ambitions to join the European Union by redrawing the border between the country along ethnic lines.

Kosovo split from Serbia in 2008, almost a decade after NATO air strikes ousted Serbian forces and halted a crackdown on ethnic Albanians during a brutal two-year counter-insurgency.