Europe's borders should not change 'at gunpoint' – Biden

U.S. Vice President Joe Biden on Tuesday blasted Russia's annexation of Crimea, saying borders should not be changed at gunpoint, as he began a visit to Romania days before a crucial vote in Ukraine.

"Europe's borders should not be changed at the point of a gun," he told Romanian and US troops at the Otopeni military airbase near Bucharest.

"We continue to condemn Russia's illegal occupation of Crimea," Biden stressed.