The UN General Assembly has approved a resolution describing the Moscow-backed referendum that led to Russia's annexation of Crimea as illegal.
It comes after the International Monetary Fund (IMF) agreed to a loan deal with Ukraine worth $14-18bn.
The US Congress also passed legislation on Thursday backing a $1bn loan guarantee for Ukraine.
Tensions are high between Russia and the West after pro-Russian troops annexed Ukraine's southern peninsula.
The West has widely condemned the move, with US President Barack Obama warning on Wednesday of "deeper" EU and US sanctions against Russia if it carried out further incursions in Ukraine.