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.

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.

He is also the US point-man in trying to get dialogue started between Russia and Ukraine over the separatist revolt in eastern Ukraine, now in its sixth year.

Since he took up the position in 2017, Volker has been regarded in Kiev as a reliable advocate for Ukraine in Washington.

Andriy Yermak, a top aide to President Zelensky, told CNN Saturday that Volker’s “consistent and comprehensive support for Ukraine throughout his tenure means a lot for our country.”

Yermak is the Ukrainian official who met with Trump’s personal attorney Rudy Giuliani earlier this year in Madrid, a meeting that Volker helped set up.

Former Ukrainian President Petro Poroshenko described Volker’s resignation as “disturbing.”

“One could hardly overestimate his contribution to strengthening of our strategic partnership with the United States,” Poroshenko said on Twitter. “With Kurt, we all were feeling more confident in Ukraine – both for a peaceful settlement and for progress on reform, and for the US role.”

The whistleblower whose complaint about Trump’s dealings with Ukraine set off the furor said his understanding was that Volker was trying to “contain the damage” inflicted on US policy by Giuliani and help Ukrainian officials “navigate” Trump’s requests.

Ukraine’s dependency on US support was evident in the Trump-Zelensky call. In the rough transcript, Trump says that “the United States has been very, very good to Ukraine.” Zelensky responds: “Yes, you are absolutely right. Not only 100% but actually 1000%.”

President Donald Trump meets with Ukrainian President Volodymyr Zelensky during the United Nations General Assembly.

US military aid to Ukraine this year amounts to nearly $400 million, part of a program to rebuild the Ukrainian military so it can better counter pro-Russian separatists that control parts of eastern Ukraine. Zelensky told Trump on the call that Ukraine wanted to buy more Javelin anti-tank missiles.

A US congressional delegation arrived in Kiev Saturday and is due to have meetings in the coming week with the Ukrainian defense minister and other senior officials.

Before leaving the US, one of the delegation, Democratic Congressman John Garamendi, said they’d be asking whether President Trump’s decision to put on hold the supply of military aid to Ukraine had caused problems for the government.

“It’s almost half a billion dollars of critical military equipment as well as the money to pay for the American trainers” working with the Ukrainian military, Garamendi told CNN.

Trump told officials to suspend the military aid program in mid-July, shortly before his call with Zelensky. The hold was lifted early in September.

Ukraine is also in the throes of negotiating new borrowing from the International Monetary Fund, in which the US has considerable influence. An IMF delegation left Kiev Friday, stressing “the importance of central bank independence and safeguarding financial stability.”

Another headache for Zelensky is the criticism of European leaders he expressed privately to Trump on the July 25 call but which became public when the rough transcript was released. He said he’d told both German Chancellor Angela Merkel and French President Emmanuel Macron that “they are not doing quite as much as they need to be doing on the issues with the sanctions” against Russia. “They are not enforcing the sanctions.”

Zelensky added that “logically, the European Union should be our biggest partner but technically the United States is a much bigger partner.”

In fact, according to data from the Organization for Economic Cooperation and Development, the European Union provided $425 million in development aid in 2016-17 – more than double the sum sent by the US. In addition, Germany alone provided Ukraine with $190 million.

Zelensky, a political neophyte who has few advisers with deep political experience, must now navigate diplomatic shoals to keep Ukraine’s main allies in Europe and the US invested in the country’s future.