With controversies swirling around Trump, the powerful House Judiciary Committee's chairman sent strongly worded letters to family members of the president as well as political confidantes and related entities.
US Democratic lawmakers launched Monday their most ambitious investigation yet into alleged obstruction of justice and abuse of office by Donald Trump, targeting dozens of individuals in the president's inner circle.
With controversies swirling around Trump, the powerful House Judiciary Committee's chairman sent strongly worded letters to family members of the president -- including sons Don Jr and Eric -- as well as political confidantes and related entities.
The letters demanded documents that could shed light on possible wrongdoing by the administration and Trump himself.
Son-in-law Jared Kushner and the Trump Organisation's longtime chief financial officer, Allen Weisselberg, were among the 81 people and organisations -- such as the National Rifle Association -- receiving letters from the panel's Democratic chairman Jerry Nadler.
They also include White House ex-aides Steve Bannon and Hope Hicks, current Trump personal lawyer Jay Sekulow, former attorney general Jeff Sessions, and WikiLeaks founder Julian Assange.
The request is the most serious overt ramp-up of investigations into Trump since Democrats took control of the House of Representatives in early January, and seeks to uncover whether Trump or his administration participated in the obstruction of justice or public corruption -- potentially impeachable offences.
"This is a critical time for our nation, and we have a responsibility to investigate these matters and hold hearings for the public to have all the facts," Nadler said in a statement.
"Over the last several years, President Trump has evaded accountability for his near-daily attacks on our basic legal, ethical, and constitutional rules and norms," he added.
"Investigating these threats to the rule of law is an obligation of Congress."
Trump himself swatted away the probe as a "political hoax," but said he would cooperate.
He later hardened his reaction, tweeting that any effort by the Democrats to probe new avenues of possible wrongdoing "will never work."
White House spokeswoman Sarah Sanders lambasted the probe as "disgraceful and abusive."
"Chairman Nadler and his fellow Democrats have embarked on this fishing expedition because they are terrified that their two-year false narrative of 'Russia collusion' is crumbling," she added.
"Their intimidation and abuse of American citisens are shameful. Democrats are harassing the president to distract from their radical agenda of making America a socialist country, killing babies after they're born, and pushing a 'green new deal' that would destroy jobs and bankrupt America."
The unusually strong statement further claimed that "the Democrats are not after the truth, they are after the president."
Conspicuously absent from the list of Nadler's targets -- who have two weeks to respond -- is the president's eldest daughter Ivanka Trump, a senior White House advisor married to Kushner.
The chairmen of three other House panels also joined the fray, demanding the White House produce details of communications between Trump and Russian leader Vladimir Putin, after reports that such information was destroyed or hidden in the aftermath of their 2017 Helsinki summit.
The US intelligence community has concluded that Russia meddled in the 2016 presidential election and that Putin ordered the influence campaign as a way to help elect Trump. The US president has repeatedly cast doubt on the findings.
Nadler's broad investigation focuses on Trump's business dealings and obstruction of justice allegations, along with possible Russian collusion.
It also will address accusations of campaign finance law violations and potential violations of the US Constitution's ban on foreign emoluments.
Trump's former personal lawyer Michael Cohen, in explosive congressional testimony last week, implicated the president in illegal activities, including a scheme shortly before the 2016 election to pay hush money to two women who say they had affairs with Trump.
One of the women reportedly received the payoffs through American Media Inc, a company run by longtime Trump ally David Pecker.
Nadler demanded information from both Pecker and AMI about their involvement.
Letters to other key players include requests for information on the June 2016 meeting in Trump Tower attended by Kushner, Trump Jr, now-jailed former campaign manager Paul Manafort and a Russian lawyer reportedly close to the Kremlin, and documents surrounding the termination of FBI director James Comey.
The expansive new probe could pave the way toward possible impeachment proceedings against Trump.
But Democratic congressional leaders, including Nadler and House Speaker Nancy Pelosi, have been reticent about pushing for the president's impeachment.
Nadler told ABC television's "This Week" that such action would be "a long way down the road."
However, he added, "it's very clear that the president obstructed justice."
In addition to the NRA, Nadler also sought documents from the White House, the Trump Organisation, Trump's charity, the FBI and Cambridge Analytica -- a data company that worked with the Trump campaign and has been investigated by Congress in connection with Russia's election interference efforts.