Biden issued a passionate plea to Vladimir Putin on Saturday, urging the Russian leader to show he truly desires peace in Ukraine.
The vice president said Russia's actions meant it was no longer trusted as an agent for peace. Russia, which last March annexed Crimea, has been accused of fomenting the conflict in eastern Ukraine by supplying support for pro-Russian rebels.
"Too many times President Putin has promised peace and delivered tanks and troops and weapons," Biden told the Munich Security Conference.
"Given Russia's recent history, we need to judge its deeds not its words," said Biden. "Don't tell us - show us, President Putin."
Biden's words came after the Russian president said his country did not want war.
Biden did not directly say that Washington would provide arms to Kyiv, but he did say it would supply security assistance.
"We do not believe there is a military solution in Ukraine. But let me be equally clear; We do not believe Russia has the right to do what they're doing."
Merkel keeps optimistic
Saturday's session of the annual Munich Security Conference began with a speech by German Chancellor Angela Merkel, who took the podium just hours after returning from Moscow, where she and French President Francois Hollande presented a new peace initiative to Russian President Vladimir Putin.
In her first direct comments since Friday's more than four hours of talks, the chancellor did not appear overly optimistic that the initiative would bring an end to the fighting between pro-Russia separatists and government forces, principally in the Donetsk and Luhansk regions.
"It is, in my view and the French president's view, definitely worth trying. We owe it to the people affected in Ukraine, at the very least," the chancellor said.
Addressing the conference a little later, Russian Foreign Minister Sergei Lavrov seemed slightly more optimistic, but laid the blame for the 10-month-old conflict squarely on the West.
"The United States and the European Union have taken steps to escalate the Ukraine crisis at every turn," Lavrov said.
He also denounced "growing appeals in the West to ... pump Ukraine full with lethal weapons and to involve it in NATO."
Chancellor Merkel had earlier reiterated Germany's position, which is strictly against supplying Kyiv with more weapons.
rc/nm (AFP, AP, dpa, Reuters)