US Vice President Joe Biden discussed problems from the Balkan's recent troubled past Tuesday in Belgrade, kicking off a short visit to Serbia and its former province of Kosovo.
A leading advocate of international intervention to stop the Balkan wars in the 1990s, the veteran lawmaker acknowledged the lingering regional tensions.
"US and Serbia naturally don't agree over every question, and there are many scars and wounds from the '90s," Biden said after meeting Serbian Prime Minister Aleksandar Vucic.
Europe needs peace in the Balkan region, he said, stressing that Serbia's progress toward EU membership "is in US interest."
An EU membership candidate, Serbia traditionally looks to its ally Russia for support and has refused to join Western sanctions against Moscow over the Ukrainian crisis.
During Biden's meeting with Vucic, the extreme nationalist, pro-Russia Radical Party staged a protest against the visit, chanting "Vote for Trump."
Biden is expected to press for a stronger campaign against corruption in Kosovo, a staunch ally of the US since it pushed NATO into intervening against Serbia to end the 1999 war.
A street in Pristina will be named after his deceased son, recognizing Biden's support for Kosovo's fight for independence from Serbia.
In Belgrade, Biden said he would push Pristina for a faster implementation of EU-brokered agreements aiming at restoring normal diplomatic ties between Kosovo and Serbia.
Serbia has not officially recognized Kosovo as an independent state.
US Vice President Joe Biden apologised in Belgrade on Tuesday to the families of those killed in NATO's four-month air strikes against Serbia and Yugoslavia in 1999, saying peace and stability in the Western Balkans now were very important for all of Europe, and praising Serbia's leadership in the region, notably in the relations with Croatia.