WASHINGTON (Reuters) - Democratic lawmakers on Friday issued a subpoena to the White House requiring him to provide all documents related to US President Donald Trump's contacts with Ukraine, which turned into a scandal involving Congress and the political center in Washington.

The lawmakers are conducting an investigation to remove Trump from office after leaking a call in which he pressed his Ukrainian counterpart to investigate corruption charges related to his potential challenger in the upcoming election, Joe Biden.

Under the new memo, the White House is obliged to submit documents on the Ukraine issue.

The following are the highlights of the Trump-Ukrainian communication scandal:

1- Phone call
On July 25, a few days after he suspended hundreds of millions of dollars in military aid to Ukraine, Trump made a phone call to his counterpart Volodymyr Zelinsky. The two men talked about "ways to strengthen relations between the United States and Ukraine," according to the White House.

Emergency problem
On August 12, a US intelligence informant wrote a Ukraine-centered statement saying it was related to an "emergency problem."

Intelligence Inspector General Michael Atkinson viewed the document as "credible" and forwarded it to US intelligence chief Joseph Maguire to send it to Congress.

After consulting with the White House and the Justice Department, Maguire concluded that this was not necessary. Atkinson then decided to take care of himself and notify Congress directly of the existence of the communication without disclosing its contents.

3 - Press reveals the hidden
On September 18, the case took on a new dimension. The Washington Post confirmed that the communication concerns President Trump's contacts with a foreign president.

She added that this talk "included a promise that caused concern" laboratory. The following day, The Washington Post and The New York Times published articles revealing that the conversation took place between Trump and the Ukrainian president.

Launch an investigation
On September 24, Democratic President of the House of Representatives Nancy Pelosi announced an investigation was launched in an effort to isolate President Trump.

5. The White House confirms
The next day, the White House released excerpts of the phone call that showed that Trump had already asked Zelinski to investigate Joe Biden. Democrats denounced what they saw as the pressure exerted on the Ukrainian president. But Trump considered isolation efforts a joke.

Strangle the scandal
On September 26, the message of the informant who accused the US president of "asking for interference" from Ukraine in the campaign for his re-election in 2020 was published.

The Democratic opposition cited the document as accusing the White House of seeking to "stifle the scandal."

7. Official note
On September 27, Democrats sent an official memo to Secretary of State Mike Pompeo, who was present during Trump's contact with Zelensky, asking him to hand them the documents necessary for their investigation, while the US special envoy to Ukraine Kurt Volcker resigned.

8. Attempt to intimidate
On October 1, Pompeo replied, accusing Democrats in Congress of "trying to intimidate" and denouncing what he called "deep legal weaknesses" in what they were doing.

Trump has demanded the arrest of deputy superintendent Adam Schiff for "treason."

Public request
On October 3, in response to the campaign, Trump called on China to investigate Joe Biden as congressional hearing of Kurt Volcker in closed session.

Democrats published text messages dating back to July showing that US diplomacy had asked the Ukrainian president to investigate Biden and his son Hunter in exchange for a meeting between Trump and Zelinsky at the White House.

10. Submission of documents
On the evening of October 4, Democratic lawmakers issued a subpoena to the White House requiring him to provide all documents related to President Trump's contacts with Ukraine.