U.S. VP Biden added that the May 25 presidential election is an opportunity to lay the groundwork for a more unified and prosperous country.
Russian President Vladimir Putin has consistently denied that Russian forces are stationed in eastern Ukraine.
The U.S. will consider more sanctions soon if Russia doesn't move to implement an agreement to ease tensions in Ukraine.
Russia Foreign Minister Lavrov urged U.S. Secretary of State Kerry to "influence Kiev, not let hotheads there provoke a bloody conflict."
Kerry urged Russia to call for separatists to vacate illegal buildings and checkpoints, accept amnesty and address their grievances politically.
Less than a week after an agreement to resolve the crisis in Ukraine, new violence has been reported in the country's east section.
So far, pro-Moscow separatist gunmen have shown no sign of surrendering government buildings they have seized.
Earlier, President Vladimir Putin said Russia would give Ukraine a month to start paying off the more than $2 billion it owes for natural gas.
Gas middlemen have been an essential part of the region’s politics, but their role may be diminishing thanks to scrutiny of their shady dealings.
U.S. Vice President Biden will offer both resource allocation and energy technology assistance during a Monday visit to Kiev.
Bank of Russia has blocked certain Ukrainian banks from operating in Crimea, leaving residents with little or no access to banking services.
The shooting deaths in Sloviansk were the first in eastern Ukraine since a deal was struck in Geneva on Thursday.
The vice president will meet with members of Ukraine's Rada parliament and representatives from non-governmental organizations.
Irma Krat's arrest may be in retaliation for violence last night that pro-Russian's blame on Euromaidan "fascists."
Could last night's deadly checkpoint attack be the straw that breaks Putin's back?
Here’s a look at Easter Sunday celebrations from around the world.
Pope Francis pleads for the end of violence and wastefulness around the world.
In St. Peter's address, Francis condemns the wastefulness that exacerbates world hunger.
"We do not connect the economy with the political process," insists the Russian president.
Pro-Russian separatists in eastern Ukraine reject a Geneva accord directing them to vacate government buildings and disband.
Despite an initial agreement by Russia, Ukraine and the West, agitators refuse to lay down their arms and vacate government buildings.
Funds reported to reduce exposure to risk in Russia.