The U.S. Congress has overwhelmingly passed legislation to provide $1 billion in loan guarantees to cash-strapped Ukraine and impose sanctions against Russia.
The votes came after the International Monetary Fund (IMF) also announced a multibillion-dollar pledge in loans to Ukraine.
The money aims at propping up Ukraine's struggling economy following three months of antigovernment protests and Russia's annexation of Crimea.
The Senate bill passed 98-2 on March 27, while the House of Representatives passed a different version on a 399-19 vote.
A final bill will have to be worked out before President Barack Obama signs it into law.
Democratic U.S. Senator Bob Menendez, chairman of the Senate Foreign Relations Committee, warned that "we are now in a dangerous moment in history."
"[Russian] President [Vladimir] Putin is watching," he said. "He is waiting to see what we'll do, waiting to see if we have the resolve to act, waiting to see if he has a green light to take the next step."
Menendez said the senate bill would authorize assistance for democracy, governance, and civil society programs. It would also sanction those responsible for human rights abuses against antigovernment protesters in Ukraine and for undermining the peace and sovereignty of the country.
"[The bill] imposes asset freezes and visa revocations on Russian officials and their associates who are complicit in or responsible for significant corruption in the Ukraine and authorizes sanctions against any Russian official engaged in corruption in the Ukraine or in Russia," Menendez added. "Putin's cronies should recognize that Putin may not be the right horse to be betting on any longer."
Earlier on March 27, the International Monetary Fund promised to loan between $14 billion and $18 billion to Ukraine.
The loan, which hinges on structural reforms that Ukraine has pledged to undertake, will unlock further credits to reach a total of $27 billion over the next two years.
In Washington, IMF deputy spokesman William Murray said the precise amount would be determined once all "bilateral and multilateral contributions" are accounted for.
During a visit to Rome, President Obama described the IMF pledge as a "major step forward."
He said the IMF support package will "help stabilize the economy and meet the needs of Ukrainian people over the long term."
With reporting by Reuters, AP, and AFP