There are increased calls among U.S. politicians to begin arming Ukraine in its fight against, what they're calling a Russian invasion.
Robert Menendez, the head of the Senate Foreign Relations Committee, said Russian President Vladimir Putin must pay for his quote "aggression."
Speaking to CNN, the Democrat said Washington should provide Ukrainians with weapons to defend themselves.
Senator John McCain echoed the sentiment and said that Putin is trying to restore the Russian empire. He called for stronger sanctions on Moscow.
The comments out of the U.S. came after Putin called for the "statehood" of eastern and southern Ukraine.
"Substantive, meaningful talks, concerning not only technical issues but also related to the issues of the society's political organization and statehood in southeastern Ukraine, should begin immediately in order to protect the legitimate interests of the people living there."
President Putin added that Russia - as a state - could not stand by and do nothing while its people were being shot at by Ukrainian forces.
Russia had previously called for "federalization" that would give greater rights to eastern Ukraine, but this is the first time Putin has called for statehood.
} Putin's spokesman later insisted that the statement did not amount to an endorsement of the separatist rebels and that only Kiev can reach an agreement with them.
Pro-Russian separatists have been gaining ground on Ukrainian forces in eastern and southern Ukraine.
The conflict erupted in April following Russia's annexation of Crimea the previous month.
Connie Kim, Arirang News.