Joe Biden warns Russia faces ‘isolation’
Mr Biden, on a visit to Ukraine where he met President Petro Poroshenko, called on Russia to withdraw its military forces from Ukraine.
Ukrainians are marking a year since the start of the uprising which ousted pro-Russian President Viktor Yanukovych.
Amid celebrations, they paid tribute to those killed over the winter in Kiev.
Ukraine formed a coalition government on Friday with a mission to overhaul the economy, fight corruption and pursue integration with the EU.
Since the ousting of Mr Yanukovych in February, Russia has annexed Crimea from Ukraine after a disputed referendum. while a separatist conflict in eastern Ukraine has cost at least 4,300 lives.
Russia is regularly accused of arming separatist rebels but its officials deny the allegations.
Read More: BBC News – Ukraine crisis: Joe Biden warns Russia faces ‘isolation’