Friction between Donald Trump and his political opponents escalated to a new level this week, with the president launching angry, personal attacks against key Democrats, most notably House Intelligence Committee chairman Adam Schiff and House of Representatives speaker Nancy Pelosi.
Schiff and Pelosi responded by insisting they are "not fooling around" in their efforts to begin impeachment proceedings against Trump. The US president is facing an investigation into a phone call in which he allegedly pressured his Ukrainian counterpart, Volodymyr Zelensky, into investigating Joe Biden, one of the leading candidates for the Democratic 2020 presidential nomination. Trump claims he is the victim of a witch hunt.
The Republican leader was also involved in tense exchanges with reporters during a press conference at the White House, in which he accused the US media of being largely "corrupt and fake".
Meanwhile, global stock markets suffered consecutive days of sharp falls, with Wall Street seeing its worst start to a quarter since 2008.
'Shifty' and 'corrupt'
Some of the president's strongest attacks and accusations were made on Twitter, where he took aim specifically at Schiff, claiming the House Intelligence Committee chairman should resign and be charged for "fraudulently making up a statement and reading it to Congress as if this statement, which was very dishonest and bad for me, was directly made by the president of the United States".
He repeated this claim when speaking to the media at the White House, dubbing the Democrat "shifty Schiff" and calling him a "dishonest guy".
Trump also criticised the opposition party in general, dubbing them the "do nothing Democrats" and saying they should be "focused on building up our country", rather than "wasting everyone's time and energy" on impeachment proceedings.
The president's anger extended beyond his political opponents, particularly during a joint press conference at the White House with Finland's president Sauli Niinisto, where he became involved in a stand-off with a journalist who asked him about his conversation with Zelensky.
Trump insisted he had "answered everything" that had been asked of him and dismissed the impeachment inquiry as "a hoax".
"And do you know who's playing into the hoax? People like you, and the fake news media that we have in this country, and in many cases the corrupt media," the president continued.
He then ordered the reporter to put a question to the Finnish president, telling him: "Don't be rude."
Democrats stand firm
Trump's political opponents sought to put up a united front against the storm of criticism from the president, with Schiff and Pelosi appearing together at a press conference in Washington.
Schiff insisted the Democrats are "not fooling around" and also raised concerns about efforts by the secretary of state, Mike Pompeo, to "potentially interfere" with witnesses whose testimony is required by the House Intelligence Committee.
"We want to make it abundantly clear that any effort - by the secretary, by the president or anyone else - to interfere with Congress' ability to call before it relevant witnesses will be considered as evidence of obstruction of the lawful functions of Congress," he said.
Pelosi had some strong words of her own for Trump.
"This president of the United States is stooping to a level that is beneath the dignity of the Constitution of the United States," she said.
Elsewhere, House Oversight Committee chairman Elijah Cummings confirmed he would issue a subpoena to the White House if it fails to submit documents relating to contact with Ukraine by the end of this week.
With impeachment proceedings underway in the US, Brexit negotiations reaching a critical point in Europe and further social unrest in Hong Kong, it has been another extraordinary week in global politics.
The drama has been reflected on the stock markets, with indexes all over the world witnessing sharp declines.
In addition to the political factors, key economic developments in the US played a big part in the market turmoil. Data showed slower job creation by American employers and a weakening manufacturing sector, while a decision by the World Trade Organisation is set to result in the US imposing tariffs on $7.5 billion of imports from the EU.
The Dow Jones Industrial Average closed more than 1.8% down on Wednesday (October 2nd), having suffered a decline of 1.3% the previous day.
In London, the FTSE 100 witnessed its worst day since January 2016, with more than 3% wiped off the value of its shares. European markets were also down.
It was a similar story in Asia on Thursday, with Japan's Nikkei 225 falling by 2% over the course of the day's trading.