Vice President Joe Biden has been speaking in Ukraine on the second day of a trip where he is showing support to the nation's fledgling pro-Western government.
In an address in Kiev on Tuesday, Biden repeated a U.S. call for Russia to pull back its military from Ukraine's borders. He said it was time for Russia to "stop talking and start acting" to de-escalate the tension that has seen the neighboring countries move to the very brink of war in recent months.
Biden also said that the U.S. will never recognize Russia's occupation of Crimea, deemed illegal by the international community, and that the White House is putting together a new package of assistance to Ukraine totaling $50 million.
Washington wants the funds to be used for political and economic reforms in a country that has long suffered from perceptions about the abuse of power.
Biden said that a separate financial aid package due from the International Monetary Fund worth up to $18 billion will soon also be finalized.
Earlier Tuesday, Biden spoke at Ukraine's parliament, saying: "The opportunity to generate a united Ukraine and getting it right is within your grasp. And we want to be your partner and friend in the project. We're ready to assist."
But Biden said that while the U.S. was prepared to support Ukraine in its attempts to secure a unified country, he urged Ukrainians to "fight the cancer of corruption that is endemic in your system right now."
He mentioned reforming the courts and finding the right balance of power between the president and parliament.
Biden also met privately with acting Ukrainian President Oleksandr Turchynov and acting Prime Minister Arseniy Yatsenyuk and later planned to meet with democracy activists, according to new agencies.
"I want you to know I do not underestimate the incredible pressure you all are under," Biden said. "I do not underestimate the challenges you all face. And I do not underestimate the frustration you all must feel when someone like me comes along to say what a great opportunity this is for you all."
He said that the upcoming elections on May 25 may be the most important in the country's history.
Separately, Russian Prime Minister Dmitry Medvedev told his nation's parliament on Tuesday, reports said, that he is working to "minimize" the consequences on the sanctions imposed on Russia following its annexation of Crimea. He also said that Russia's economy is facing intense pressure as a result of a poor world economy.
Contributing: Associated Press