U.S. Vice President Joe Biden has accused Russia of trying to destabilize Ukraine “by any means it can,” saying the Kremlin wants to see the economy of its ex-Soviet neighbor crumble.

"Russia’s trying to undermine the stability and the sovereignty of Ukraine by any means it can, including its attempt to create conditions that will cause Ukraine to economically collapse,” Biden told U.S. and Ukrainian officials and business leaders in Washington on July 13.

"That’s [Russia’s] first preference," Biden added. "But we can’t let that strategy succeed."

Biden delivered the comments in a speech to the inaugural U.S.-Ukraine Business Forum, an event co-hosted by the U.S. Commerce Department aimed at fostering U.S. investment in the Ukrainian economy, which has been ravaged by Kyiv’s war with Russian-backed separatists in the east of the country.

Biden repeated allegations by Kyiv, Washington, and their allies in Brussels that Moscow is backing the rebels, saying Ukraine is “now under siege.”

"Russia is building military outposts on Ukrainian soil," Biden said. "It relentlessly continues to send Russian troops, Russian hired thugs and mercenaries, Russian tanks, and Russian missiles into numerous parts of Ukraine, but particularly the Donbas."

The Kremlin denies it is supporting the separatists, despite mounting evidence of Russia military involvement in the conflict, which has killed more than 6,500 since the fighting erupted in April 2014.

Biden also urged Ukraine to enact reforms, crack down on endemic corruption, and improve transparency in order to lure investors to the country, saying the leadership in Kyiv has a small window of opportunity to secure greater integration with the West.

"This may be the last genuine opportunity the people of Ukraine have to establish a democratic republic in a way that is economically prosperous and fully integrated within Europe," he told the forum.

The audience included senior Ukrainian officials, including Prime Minister Arseniy Yatsenyuk and Finance Minister Natalie Jaresko, a U.S. citizen, both of whom addressed the forum earlier in the day.

Ukraine has been locked in tense negotiations with creditors as it seeks to restructure its debt. Kyiv has threatened to halt payments on its international debt if creditors refuse to agree to a writedown on the holdings.

Addressing the forum, Yatsenyuk called on the creditors to "be cooperative and collaborative." He also said the Ukrainian government is taking concrete steps to tackle corruption, while conceding that graft remains a deeply rooted problem in the country.

"Please, American investors, jump in. We are happy to see you in Ukraine," Yatsenyuk said.

Biden told the audience that Kyiv must “confront the corruption that has kept this country from taking advantage of the tremendous human capital it possesses.”

"To attract the type of investment that will allow Ukraine to survive and thrive, the changes being enacted now have to be real and have to be lasting," Biden said. "They cannot just be reforms on paper. They have to be tangible for businesspeople, for civil society, and for ordinary citizens on the street for any of it to work."

With reporting by VOA and Bloomberg