Among the various groups reacting angrily to President Donald Trump's Helsinki press conference with his Russian counterpart are a congressional bipartisan caucus focused on Ukraine and the head of Ukraine's parliamentary foreign affairs committee.

In a Tuesday evening statement signed by the co-chairs of the Congressional Ukraine Caucus, Democratic Reps. Marcy Kaptur of Ohio and Sandy Levin of Michigan, and Republican Rep. Brian Fitzpatrick of Pennsylvania, said they were "deeply troubled by the president's subservient behavior towards President Putin," Voice of America reports.

"The United States must never tolerate actions that seek to weaken democratic institutions in the U.S. and our allies abroad," the statement said. "Russia's illegal invasion of Ukraine and its assault on peace and security in Europe has led to the death of thousands of Ukrainians and the displacement of millions."

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The legislators also expressed concern that Trump didn't condemn Russia's "assault on Ukraine's sovereignty, including cyberattacks on its institutions, aggression in the Donbass [sic] region, and the illegal occupation of Crimea," the first forcible transnational seizure of territory in Europe since World War II.

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"We urge President Trump to stand shoulder-to-shoulder with our NATO allies in the face of continued threats from Russia and its aggression in Ukraine," the statement said.

Hanna Hopko, head of the Ukrainian parliamentary Committee on Foreign Affairs, told VOA that officials in Kyiv monitored the summit, expecting to see statements on Ukrainian issues.

"Of course it's in Ukraine's interest to see a strong America and not a weakening of the [U.S.] position by statements that could be perceived as a step back," Hopko said. "And we expect to see strength from the United States and a dedication to the rule of law and trust in the intelligence services of the United States."

Beyond Russia's occupation of Crimea and military support for secessionists in the country's eastern Donbas region, Kyiv officials have raised alarm about Russian interference in Ukraine's political affairs.

With parliamentary elections on the horizon, Hopko said, White House support for the U.S. indictments of 12 Russian military intelligence officials, who face charges of meddling in U.S. politics, will prove vital.

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"It's really important for Kyiv to see a successful example of an investigation of Russian interference in foreign democratic elections," Hopko said.

"We've seen a lot of cases of Russian interference in France, in Italy, in Germany, in the U.K.," she said, adding that a U.S. probe resulting in prosecutions could discourage Moscow from further meddling abroad.

Like the bipartisan U.S. caucus that condemned the Helsinki summit, Hopko said Kyiv officials were discouraged that Trump failed to mention Russian aggression in Ukraine.

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"We just wanted to hear Trump's position that Crimea belongs to Ukraine, and that this is the firm, unchangeable position of the United States," she said. "Instead, Putin did his job and said 'there's a difference of view' on Crimea."

The wording that Putin used on Monday to describe the Kremlin-orchestrated referendum on the annexation of Crimea, Hopko added, prove that the 2014 vote violated international law.

Putin, Hopko said, referred to "the referendum 'we conducted,' meaning Russia interfered and conducted a fake referendum to legitimize their illegal annexation of Crimea."