US Secretary of State John Kerry arrived in Kiev to hold talks with Ukraine's interim President Oleksandr Turchynov and pledged $1 billion in loan guarantees, according to a senior State Dept official.
Kerry landed in the Ukrainian capital to show US support for the Ukrainian government in its struggle against the Russian occupation of Crimea.
Kerry is also set to offer technical assistance to the new government as the West seeks to draw the country closer to the European Union and away from Russia's sphere of influence following Vladimir Putin's decision to send military forces to occupy the Crimea Peninsula.
The loans and assistance that Kerry has pledged are to assist Ukraine in its integration with the West and counter the benefits of Russian energy subsidies.
Technical experts will be sent to aid Ukraine's infrastructure, such as the national bank and finance ministry, while providing advice on tackling corruption and training for election monitors to ensure that the upcoming May 25 Ukrainian election is legitimate, according to the New York Times.
The loan package comes as Western powers ponder the correct course of action to tackle Russian aggression in Eastern Europe, with sanctions the most likely option at this stage.
It is the latest move in the struggle for influence over Ukraine in the 'shared neighbourhood' between the European Union and Russia.
Russia has said it will consider loaning Ukraine between $2bn (£1.2bn, €1.45bn) and $3bn to help it pay for a gas bill from Gazprom, the Russian state-owned energy giant, in an attempt to keep the country out of the arms of the European Union.
Follow our live blog on developments in Ukraine here.