The impeachment case against Donald Trump has now been laid out by House Democrats, in a sweeping report that accuses the US President of betraying the nation.

Key points: Donald Trump faces two articles of impeachment brought by Democrats

Donald Trump faces two articles of impeachment brought by Democrats It is only the third time in US history the House will be voting on impeaching a president

It is only the third time in US history the House will be voting on impeaching a president The House will vote this week; a Senate trial is expected early next year

The Democratic-led House of Representatives will vote this week on charges stemming from Mr Trump's alleged effort to pressure Ukraine to investigate Democratic political rival Joe Biden.

No Republicans are breaking with the President but almost all Democrats are expected to approve the charges against him in the vote on Wednesday (local time).

Mr Trump faces two articles of impeachment brought by Democrats.

They said he abused the power of his office by pressuring Ukraine to investigate Mr Biden and obstructed Congress by trying to block the House investigation and its oversight duties as part of the nation's system of checks and balances.

Monday's 650-page report from the House Judiciary Committee said the President "betrayed the nation by abusing his high office to enlist a foreign power in corrupting democratic elections".

He withheld military aid from the ally as leverage, the report said, and Mr Trump, "by such conduct, has demonstrated that he will remain a threat to national security and the constitution if allowed to remain in office".

The report said the President then engaged in an unprecedented attempt to block the investigation and "cover up" his misconduct.

"In the history of the republic, no president has ever ordered the complete defiance of an impeachment inquiry," it added.

President Donald Trump tweeted again on Monday, insisting he had done nothing wrong. ( AP: Evan Vucci )

Mr Trump, tweeting from the sidelines after instructing the White House not to participate in the House inquiry, insisted he had done nothing wrong.

Sticking to the language he has relied on for months, he tweeted on Monday: "The Impeachment Hoax is the greatest con job in the history of American politics!"

It is only the third time in US history the House will vote on impeaching a president.

As the House outlined its case, attention was turning to the Senate where Democratic leader there, Chuck Schumer, called anew for fresh evidence and testimony from key White House officials for the Senate impeachment trial.

In a letter to Senate majority leader Mitch McConnell, Mr Schumer proposed hearing testimony from former national security adviser John Bolton, acting White House chief of staff Mick Mulvaney and two others as part of a detailed offer he made to Republicans as an opening offer for negotiations.

"If Leader McConnell doesn't hold a full and fair trial, the American people will rightly ask, what are you, Leader McConnell, and what is President Trump hiding?" Mr Schumer said.

The trial, on whether to remove Mr Trump from office, is expected early next year.

Republicans hold 53 of the 100 seats in the Senate, where they appear likely to prevail in any trial against Mr Trump, which would require a two-thirds majority of those present to remove him from office.

Democrats, who enjoy a 36-seat majority in the House, are expected to win an impeachment vote this week, which requires a simple majority.

AP/Reuters