Photo from UNIAN

Democrats pursuing an impeachment inquiry of U.S. President Donald Trump want to take a fresh look at whether the sale of anti-tank missiles to Kyiv last year was in any way connected to Ukraine's decision to halt investigations into Trump's campaign chairman.

The renewed interest in the circumstances surrounding the sale of Javelin anti-tank missiles – long coveted by Ukraine as a way to fend off Russian aggression in the east – has been spurred by revelations about the Trump administration's dealings with the newly elected president, Volodymyr Zelensky. It raises the prospect that the president, or his aides, may have been pressuring the Ukrainian government in exchange for political favors far earlier than previously known, POLITICO reported.

"I think that's all part of the fact finding that members of the six committees need to pursue, and as a member of the foreign affairs committee, it's something that I'm very interested in," said Representative Jim Costa in an interview.

Read alsoCNN: House Democrats subpoena Energy Secretary Perry for Ukraine documents in impeachment inquiry

House foreign affairs committee members Representative Gerry Connolly and Tom Malinowski are also interested.

"It certainly is on the list of inquiries to be pursued," Connolly told POLITICO on Tuesday, saying the question of potential "extortion" of Ukraine will be "a major part of the impeachment inquiry."

"I intend to ask about it," added Malinowski.

The U.S. completed its shipment of Javelin anti-tank missiles to Ukraine in May 2018, finalizing a sale that was pushed by lawmakers in both parties and reluctantly approved by Trump in November 2017. In April 2018, then-Ukrainian President Petro Poroshenko ordered Ukraine's top anti-corruption prosecutor Yuriy Lutsenko – who'd been tasked with investigating corruption that occurred under former Ukrainian President Viktor Yanukovych – to stop cooperating with special counsel Robert Mueller.

Mueller, at that point, was investigating former Trump campaign chairman Paul Manafort's work for Yanukovych in Ukraine and his ties to Russia.

Read alsoWhy the Trump scandal is good for Ukraine – media

Democratic Senators Dick Durbin, Bob Menendez and Patrick Leahy sent a letter to Lutsenko on May 4, 2018, expressing their "great concern" about reports that the investigation had been impeded – and asking directly whether "any individual from the Trump administration, or anyone acting on its behalf" encouraged Ukrainian government or law enforcement officials not to cooperate with the Mueller probe. They never received a response, according to a spokesman for Democrats on the Senate foreign relations committee.

There was no evidence at the time that Trump had directly asked the Ukrainians to halt the cooperation, and a New York Times report indicated that the Ukrainians had done it of their own volition to stay on the president's good side.

A person familiar with the matter said refraining from selling Javelins to Ukraine had been "a bad policy in the Obama administration" that top Trump administration officials including then-Defense Secretary Jim Mattis and then-Secretary of State Rex Tillerson were eager to reverse. (The Obama administration's hesitance to approve the sale of the Javelins, officials said at the time, was primarily due to their concern that Russia, which was pouring troops and weapons into eastern Ukraine, could use the missiles as a pretext to escalate the conflict.)

The source acknowledged that it "took a few rounds for the president to get his support" before he signed off on it, but said he "wasn't aware of anything related to Mueller at that time."

Read alsoU.S. officially launches procedure of selling Javelin missile systems to Ukraine

Still, other sources said at the time that Trump wasn't looking to sell the Javelins to the Ukrainians for nothing. To get him on board, Trump's national security advisers emphasized that this would be a sale, not a gift, said a U.S. official with direct involvement in the matter.

And Poroshenko won favor with Trump by facilitating an $80 million coal deal – the first between the U.S. and Ukraine – that was politically expedient for both leaders. Less than two months after the State Department approved the sale, Ukrainian Railways signed a $1 billion locomotive deal with GE Transportation, which boosted Trump's campaign promise to revitalize the U.S. rail industry.

Now, Democrats want to know if there were other incentives at play – especially in light of Zelensky's comment, in his July call with Trump, that Ukraine is almost ready to buy additional Javelins from the U.S. "for defense purposes." Trump responded by asking for "a favor" – namely, that Zelensky investigate Ukraine's involvement in the 2016 election, with help from the attorney general.