(Recasts with Trump comments on Biden, House intelligence panel report finding, details on impeachment process)
By Steve Holland and Susan Heavey
LONDON/WASHINGTON, Dec 3 (Reuters) - U.S. President Donald Trump on Tuesday used a global stage to attack Democrats' impeachment inquiry into whether he pressured Ukraine to investigate former Vice President Joe Biden, and demanded again that his political rival testify in the proceedings.
Trump, speaking on the sidelines of a NATO summit in London, complained that Democrats in the U.S. House of Representatives had conducted unfair "witch hunt" hearings in which witnesses the administration wanted to testify were not called.
Senior administration officials have declined to testify in the proceedings.
"We want Biden. We want the son — Where's Hunter? We want the son," Trump said during a meeting with Canadian Prime Minister Justin Trudeau.
Trump and other Republicans have suggested that Biden and his son, who was on the board of a Ukrainian energy company for several years, should be investigated for corruption. There is no evidence that either of the Bidens engaged in wrongdoing.
Joe Biden is a leading contender for the Democratic nomination to face Trump in the 2020 presidential election.
The Democratic-controlled House Intelligence Committee, which has spearheaded the impeachment probe that formally began in September after a whistleblower's complaint, is scheduled to meet at 6 p.m. EST (2300 GMT) to vote on its findings.
The committee released a report on Tuesday laying out its case to impeach Trump. It said Trump "solicited the interference of a foreign government, Ukraine, to benefit his reelection."
The matter will go to the House Judiciary Committee, which will open its proceedings on Wednesday.
Trump also rejected an idea floated by some members of Congress that he be censured for his handling of the Ukraine scandal as an alternative to being impeached.
"I did nothing wrong," Trump said. "You don't censure somebody when they did nothing wrong."
Trump has accused Democrats of using the impeachment process to overturn the results of the 2016 presidential election as he seeks re-election next November. Opinion polls show Americans are bitterly divided over whether to impeach Trump.
If the full House eventually votes to approve formal impeachment charges, a trial would be held in the Republican-led U.S. Senate, where a two-thirds majority of those present would be required to convict and remove Trump from office.
There is widespread doubt that Trump's fellow Republicans in the Senate are willing to do that, although some lawmakers have raised the idea of a censure in recent days as a way to rebuke his actions without the risk of ending his presidency.
At issue is whether Trump misused the power of his office to pressure Ukraine to investigate the Bidens.
Lawmakers and the public have heard testimony from current and former officials that military aid was withheld from Ukraine and that a White House meeting with Ukrainian President Volodymyr Zelenskiy was conditioned on Kiev conducting the probe as well as one into a debunked conspiracy theory about Ukraine interference in the 2016 U.S. election.
U.S. Under Secretary of State for Political Affairs David Hale, the No. 3 State Department official, told a Senate Foreign Relations Committee hearing on Tuesday that he had seen no evidence that Ukraine interfered in the 2016 elections, undermining an argument used by Trump and some of his supporters.
House Intelligence Committee Chairman Adam Schiff, in an interview with MSNBC on Monday night, said the committee would continue its investigation after the release of its report on Tuesday and while the judiciary panel did its work.
House Democrats appear to be contemplating at least two possible articles of impeachment tied to the Ukraine scandal: abuse of power and obstruction of Congress. There does not yet seem to be a robust discussion yet on going beyond those articles of impeachment, a senior House Democratic aide said.
Republicans, in an advance rebuttal report released on Monday, said Democrats had not established that Trump had committed an impeachable offense.
The president and other administration officials have criticized the timing of this week's impeachment proceedings as Trump attends the summit overseas, although former Democratic President Bill Clinton also faced impeachment during a 1998 trip to Israel.
In London, Trump repeated his defense that his calls with Zelenskiy, including one on July 25 in which he pushed for the probe of the Bidens, were "perfect" and that the impeachment inquiry was "a hoax."
(Reporting by Steve Holland in London and Susan Heavey in Washington Additional reporting by Richard Cowan, David Morgan, Patricia Zengerle, Jonathan Landay, Susan Cornwell and Mark Hosenball in Washington Writing by Susan Heavey and Paul Simao Editing by Jonathan Oatis and Grant McCool)
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