Democratic lawmakers have demanded that the White House turn over documents related to U.S. President Donald Trump's efforts to get Ukraine to investigate a political rival, or face a congressional subpoena.
Chairmen of three House of Representatives committees leading the investigation on October 2 said the White House must comply by October 4 or face a subpoena for documents mainly related to Trump's controversial July 25 phone call with Ukrainian President Volodymyr Zelenskiy.
The U.S. administration has so far resisted turning over documents, while the State Department has pushed back on demands by Congress that five current and former department officials provide depositions and turn over requested documents on the matter.
"The White House's flagrant disregard of multiple voluntary requests for documents -- combined with stark and urgent warnings from the [intelligence community's] Inspector General about the gravity of these allegations -- have left us with no choice but to issue this subpoena," the committee leaders said in a memo.
The panel chairmen are Adam Schiff of Intelligence, Elijah Cummings of Oversight, and Eliot Engel of the Foreign Affairs.
Democrats have already subpoenaed Secretary of State Mike Pompeo and Trump's personal lawyer Rudy Giuliani for any documents related to Ukraine.
Attention has intensified on the State Department in the impeachment inquiry, with two former diplomats set to appear before Congress and Pompeo confirming he listened in on the July 25 call with the Ukrainian leader.
Pompeo, speaking during a news conference while traveling in Italy, acknowledged he "was on the phone call" that Trump had with Zelenskiy that spurred the impeachment inquiry against the U.S. president, who has called the process an attempt at a “coup” by his Democratic Party rivals.
Pompeo gave no further details about the call in response to questions during the news conference with his Italian counterpart Luigi Di Maio in Rome.
While it is not unprecedented to have a secretary of state listen in on a call between the U.S. president and a foreign leader, Pompeo had previously avoided answering questions about his possible involvement in the conversation.
In the wake of a whistle-blower complaint last week, Democrats are investigating Trump's request during the July 25 phone call with Zelenskiy to investigate former Vice President Joe Biden and his son, Hunter, who had business dealings in Ukraine.
The unidentified whistle-blower raised concerns that Trump was pressuring the Ukrainian president by threatening to withhold U.S. military aid and soliciting foreign interference in exchange for personal gain.
Biden is one of the main contenders in the race for the Democratic presidential nomination to run against Republican Trump in the 2020 election.
Trump has denied any wrongdoing and has called the inquiry "the greatest scam in the history of American politics.”
In a social media post on October 1, Trump said that "as I learn more and more each day, I am coming to the conclusion that what is taking place is not an impeachment, it is a COUP."
In a Twitter post on October 2, Trump wrote that Democrats were wasting "everyone's time and energy on BULLSHIT."
Pompeo has tried to delay five current and former officials from providing documents and testimony in the inquiry, claiming Democrats were trying to "intimidate” and "bully" State Department officials.
However, Democrats were able to set closed-door depositions with ousted U.S. Ambassador to Kyiv Marie Yovanovitch and Kurt Volker, former special envoy to Ukraine.
Yovanovitch has agreed to appear before the panels on October 11. The veteran diplomat was abruptly recalled from Kyiv by Trump in May, two months ahead of schedule.
Volker is scheduled to appear before the House committees on October 3. The former special envoy resigned suddenly and without explanation on September 27 after his name was mentioned in the whistle-blower complaint.
Volker resigned when it emerged that he had followed up with Ukrainian officials a day after the Trump-Zelenskiy call.
In a news conference on October 2, Schiff said that "we are deeply concerned about Pompeo's effort now to potentially interfere with witnesses whose testimony is needed before our committee, many of whom are mentioned in the whistle-blower complaint.
"And we want to make it abundantly clear that any effort by the secretary, by the president, or anyone else to interfere with the congress's ability to call before it relevant witnesses will be considered obstruction of the lawful functions of congress," the Democrat added.
Trump had abruptly frozen nearly $400 million in military funding to Ukraine ahead of the call.
The funds have since been unlocked and Congress and the State Department have given initial approval to sell Kyiv $39 million worth of anti-tank missiles to help it battle Russian-backed separatists in the eastern part of Ukraine.
The pending sale, requested this summer, is not part of the aid that Trump had withheld.
The United States has been providing military aid to Ukraine since Russia invaded in 2014.
In the wake of the scrutiny over Trump's conversation with Zelenskiy, Democrats have said they are determined to get access to the U.S. president’s calls with other leaders, including Russian President Vladimir Putin.
Putin on October 2 said he would not object to the transcripts of his calls with Trump being published and that he always assumes his words could potentially be made public whenever he speaks.
Critics have expressed concerns that Trump secretly made concessions to the Russian leader, with whom he has made clear he is seeking to improve relations despite U.S. intelligence services' conclusions that Moscow interfered with the 2016 presidential election to aid Trump.