BELGRADE, Serbia (AP) — Serbia's president says he doesn't share U.S. President Donald Trump's optimism that an agreement between Serbia and Kosovo is "within reach" two decades after their war.

Serbian President Aleksandar Vucic said Friday that a letter sent by Trump expressing that opinion is "rational" and welcome, but also added: "We are far from any kind of agreement."

In almost identical letters to the Serbian and Kosovo leaders, Trump has urged the two to secure a "historic" deal that would bring "long-sought" peace to the Balkan region.

Serbia and Kosovo have been conducting European Union-mediated talks aimed at normalizing relations. Kosovo declared independence in 2008 from Serbia, a move Belgrade rejects.

Trump's letter is seen as sign that Washington is willing to take a more active role in mediating between the two foes.