Vice president Joe Biden hopes to demonstrate the US commitment to Ukraine by meeting with its leaders as they deal with their confrontation with Russia.
Mr Biden arrived yesterday for a two-day visit to the capital Kiev.
He has meetings today with the acting Ukrainian prime minister and president.
He is also scheduled to meet with legislators and democracy activists before returning to Washington tonight.
He plans to announce new technical support to the Ukrainian government to implement energy and economic reforms.
On Sunday, Ukraine and Russia blamed each other for a shoot-out at a checkpoint manned by pro-Russia insurgents in eastern Ukraine that left one person dead and others in hospital with gunshot wounds.
The identity of the attackers remained unclear. Russia blamed militant Ukrainian nationalists and the Ukrainian government said the attack near the city of Slovyansk was staged by provocateurs from outside the country.
The armed clash appeared to be the first since an international agreement was reached last week in Geneva to ease tensions in eastern Ukraine, where armed pro-Russia activists have seized government buildings in at least 10 cities.
Ukraine and many in the West fear that such clashes could provide a pretext for Russia to seize more Ukrainian territory. Russia, which annexed the peninsula of Crimea last month, has tens of thousands of troops along its border with Ukraine. Russian officials, including President Vladimir Putin, originally said the troops were there for military exercises, but the president’s spokesman on Sunday acknowledged that some were there because of instability in eastern Ukraine.
The self-proclaimed mayor of Slovyansk appealed to Russia yesterday to send in peacekeeping troops. “They are killing our brothers,” Vyacheslav Ponomaryov said during a news conference in Slovyansk.