KYIV -- Making his final visit to Kyiv in eight years as U.S. vice president, Joe Biden urged the international community to stand against what he called Russian aggression and urged the incoming administration of President-elect Donald Trump to be a strong supporter of Ukraine.
Biden’s visit, his sixth during President Barack Obama's eight years in office and fifth since Moscow-friendly President Viktor Yanukovych fled in the face of the Euromaidan protests in February 2014 and a pro-Western government came to power, came four days before Trump's January 20 inauguration.
Speaking alongside Ukrainian President Petro Poroshenko, whom he described as his "good friend," Biden said U.S. sanctions imposed on Russia for its seizure of the Crimean Peninsula and its involvement in a war between government forces and pro-Moscow separatists in eastern Ukraine must remain in place until Moscow fully implements its commitments under a 2015 peace deal known as the Minsk accords.
WATCH: Biden Urges Ukraine To 'Root Out' Corruption
Biden said he knows it is hard to find faith in the Minsk process when Russia refuses to hold up its end of the deal, in his words, but he emphasized that it is "Ukraine’s best hope to move forward as a united country."
The outgoing U.S. vice president urged Ukraine to keep demonstrating its commitment to the rule of law and fighting corruption. He said Ukrainians must insist on transparency and "investigate and prosecute government officials who siphon off funds for their own enrichment."
Russia, Biden said, has used corruption as a "tool of coercion" to keep Ukraine within its sphere of influence. Fighting corruption is not just a matter of good governance, it is essential for self-preservation and security, he said.
Poroshenko expressed gratitude to Biden for his unwavering support for Ukraine and invited him back to Kyiv as a private citizen.
He also thanked the United States for Obama's January 13 decision extending sanctions against Russia over its seizure of Crimea and aggression in eastern Ukraine for a year, through March 2018 -- a move that means Trump will have to cancel them rather than just letting them expire in a few weeks if he wants to abandon them, as he has indicated he might.
In the future, Poroshenko said, he hopes the "Ukrainian issue will unite all American politicians and will remain among their top priorities.
"Everyone who shares democratic values is Russia's adversary," he said.
The Ukrainian president also welcomed what he called "encouraging signals delivered during Senate hearings by the candidates for secretary of state and secretary of defense,” he added, referring to former ExxonMobil CEO Rex Tillerson and retired General James Mattis, respectively.
During hours of questioning last week, the nominees took tougher positions on Russia than Trump has, both regarding Moscow's interference in Ukraine and allegations of interference in the U.S. presidential election.
Ukrainian officials have expressed concern that U.S. support could wane following the inauguration of Trump, who has spoken admiringly of Russian President Vladimir Putin and expressed a desire to improve ties with Moscow.
In an interview with The Times of London and the German magazine Bild published on January 16, Trump suggested he may offer to roll back sanctions against Russia in return for a deal with Moscow to reduce nuclear arms.
Ukrainians have become fond of Biden, who has become known in political circles in Kyiv as "Uncle Joe" for what Taras Berezovets, a political consultant and founder of the Kyiv-based think tank Ukrainian Institute for the Future said was his ability to intervene and quash spats between Ukrainian officials before they spiraled out of control.
"[Biden] would always show up at the right moment with the right words and always stop internal political crises," he told RFE/RL.
Berezovets also said that "Biden’s intervention in Ukrainian [affairs] was absolutely vital for defending our independence, because in 2014 there was a clear and present danger of a full-scale Russian offensive against Ukraine...and I think the intervention of Biden and Obama in terms of political and diplomatic pressure was significant enough to stop that escalation."
During his visits and frequent phone calls, Biden has pressed Ukrainian leaders to tackle deep-seated corruption that he has frequently warned weakens Kyiv's ability to protect itself against Russian interference.
In a speech to parliament in Kyiv in December 2015, he told lawmakers they needed to do more in "a historic battle against corruption."
"The world is watching you. This is your moment," he said at the time. "Please, for the sake of the rest of us, don’t waste it."
He reiterated that message a little more than one year later on January 16, saying: "I believe the Ukrainian people are no longer willing to postpone a free, democratic, prosperous Ukraine. So seize it."
After reading his statement, Biden was asked by a reporter if he had received any assurances that the Trump administration would place a similar priority on Ukraine.
"Hope springs eternal," he replied before flashing a thumbs up, turning, and walking away.