Democrats in the U.S. House of Representatives have said they are launching a formal impeachment inquiry into President Donald Trump for "betraying" his oath of office amid allegations he pressed Ukraine to investigate a rival politician.
House Speaker Nancy Pelosi said late on September 24 that the move was necessary because of Trump's "betrayal of his oath of office, betrayal of our national security, and betrayal of the integrity of our elections."
Pelosi had long been against launching such an inquiry but reversed her position after reports that Trump had pressured Ukrainian President Volodymyr Zelenskiy in a July 25 telephone call to investigate former Vice President Joe Biden, and his son Hunter, who had worked for a company drilling for gas in Ukraine.
"The president must be held accountable. No one is above the law," Pelosi said in a televised address on September 24.
"Therefore, today I'm announcing the House of Representatives is moving forward with an official impeachment inquiry," she said.
Trump has acknowledged that he discussed the Bidens during the call, but he has strongly denied pressuring Zelenskiy, a 41-year-old political novice.
Earlier in the day, however, Trump confirmed he told staff to freeze almost $400 million in aid to Ukraine just ahead of the call.
There is no evidence that Joe Biden, one of the top candidates for the Democratic nomination to challenge Trump in the 2020 election, did anything illegal related to Ukraine.
In a span of nine minutes from Pelosi's announcement, Trump posted a flurry of tweets calling Pelosi's inquiry "a total Witch Hunt!" as well as "presidential harassment!"
The July call between Trump and Zelenskiy came to light after it reportedly became the subject of a whistle-blower's complaint lodged with the inspector-general for the intelligence community. U.S. media have reported that the complaint was filed in August.
Acting Director of National Intelligence Joseph Maguire has determined the whistle-blower's complaint could not be forwarded to Congress.
Lawyers for the whistle-blower said on September 24 that they were seeking guidance on how to protect their client if they want to meet with congressional intelligence committees regarding the complaint.
The two attorneys say their client, a member of the U.S. intelligence community, is waiting for a "timely response" from Maguire, according to the AP.
However, the Trump administration said the same day that the White House was preparing to release the complaint to Congress by the end of the week.
Adam Schiff, chairman of the House of Representatives' Intelligence Committee, also said testimony could be "as soon as this week."
Pelosi cited the administration's refusal to turn over the whistle-blower complaint, as required by law, that reportedly expresses alarm over promises made by Trump during the phone call with Zelenskiy on July 25.
In an interview with Voice of America at the United Nations, Zelenskiy on September 24 didn't elaborate about being pressured, saying that "we are an independent country, we are ready for everything."
Zelenskiy is expected to meet with Trump on September 25 on the sidelines of the UN General Assembly.
House Republican leader Kevin McCarthy, who didn't support Pelosi's formal inquiry, said her actions "do not speak for America when it comes to this issue.... She cannot unilaterally decide we're in an impeachment inquiry."
Under the constitution, the president can be removed from office for "treason, bribery, or other high crimes and misdemeanors."
Two presidents -- Andrew Johnson in 1868 and Bill Clinton in 1998 -- have been subject to impeachment proceedings, with both being acquitted in the Senate. The House approved articles of impeachment against Richard Nixon in 1974, but he resigned before proceedings began – the only resignation in U.S. presidential history.
Articles of impeachments are generally initiated in the House Judiciary Committee before being passed on to the full House for a vote.
But a trial is held in the Senate where that chamber's lawmakers act as jurors and the chief justice of the U.S. Supreme Court presides during proceedings in which House members act as prosecutors.
A conviction and removal from office are unlikely because Trump's Republican Party controls the Senate.​
Pelosi has come under pressure from many Democratic lawmakers and presidential candidates for her apparent reluctance to call for an impeachment of the president. Many experts said she feared such a move, with almost no chance of success in the Senate, could fire up Trump supporters ahead of the 2020 elections.
Pelosi would appear to have enough votes in the Democratic-led House to move on to actual impeachment proceedings, although many of her fellow party members have also expressed caution about such a dramatic move.
As calls for resignation mounted by Democrats, Trump earlier on September 24 said his administration would release the "complete, fully declassified and unredacted" transcript of the controversial July phone call in which he asked to investigate a political rival.
"You will see it was a very friendly and totally appropriate call. No pressure," he wrote in a tweet.
The Republican-controlled Senate on September 24 approved a nonbinding resolution that calls on the Trump administration to provide the House and Senate intelligence committees a copy of the whistle-blower's complaint involving the president.
Speaking to reporters at the United Nations, Trump said he made the move to combat corruption and push European countries -- singling out France and Germany by name -- to "put up money" to help Ukraine.
"As far as withholding funds, those funds were paid," Trump said, calling allegations that he pressured Zelenskiy "ridiculous."
Since 2014, the EU and European financial institutions have mobilized a package of more than 15 billion euros ($16.5 billion) in grants and loans to support Ukraine's reform process, according to the bloc.