The US State Department issued an initial response to a Congressional request for documents as part of the impeachment inquiry of President Donald Trump, Secretary of State Mike Pompeo said on Saturday.

As the US House Democrats on Friday subpoenaed the White House for documents they want to see as part of their ongoing Trump impeachment investigation, the State Department has issued an initial response, Secretary of State Mike Pompeo said on Saturday during a press conference in Greece.

“The State Department sent a letter last night to Congress, which is our initial response to the document request. We will obviously do all the things we are required to by law,” Pompeo said.

He made clear that while the State Department had yet to turn over any document, it intended to follow a proper review, adding that he would do so faster than the Obama administration.

"I remember precisely once when I was on that side and we were looking for documents, I remember precisely how long it took for those documents to come across," he said in an apparent reference to his experience as a congressman during the investigation into the 2012 attack on the US mission in Benghazi, Libya. We're going to beat that. We're going to be more responsive than the Obama administration was in the years that preceded this particular Congress," he said.

A congressional aide familiar with Pompeo's response confirmed to the Associated Press that the State Department had been in contact, even if Pompeo had failed to meet a Friday deadline to produce documents required by the subpoena.

On 24 September, Democrats launched an impeachment inquiry into Trump’s 25 July telephone call with Ukrainian President Volodymyr Zelensky. The inquiry was initiated after a whistleblower sent a complaint to Congress, saying that Trump had pressed Zelensky to investigate possible corruption by 2020 Democratic presidential candidate Joe Biden and his son Hunter and implicitly threatened to withhold US military aid to Ukraine.Trump denied the allegations, calling them another attempt at a political witch hunt to reverse the outcome of the 2016 US presidential election. Pompeo, who has also become a key figure in the Democrats' inquiry, said there were ‘clearly politics’ involved in the investigation.