Kiev, Ukraine (CNN) There's a growing sense of alarm in Ukraine that it will be the victim of any prolonged political crisis in the United States over President Trump's controversial contacts with the new Ukrainian leader, Volodymyr Zelensky.

Ukrainian officials are declining to discuss the fall-out from the phone call between the two presidents on July 25, and whether they believe Trump was trying to put pressure on Zelensky to order corruption investigations into former Vice President Joe Biden and his son Hunter.

For Ukraine, there's no upside in getting embroiled in the US maelstrom.

Whatever officials here say, gratifying one side risks antagonizing the other. And in the process, Ukraine's deep reliance on US assistance -- financial, military and diplomatic -- risks being compromised.

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The first sign of trouble came with the resignation of the US special envoy to Ukraine, Kurt Volker. Volker has been at the heart of efforts to keep US military and economic aid flowing to Ukraine.