WASHINGTON (Reuters) - U.S. President Donald Trump solicited foreign interference to boost his re-election chances, undermined national security and ordered an “unprecedented” campaign to obstruct Congress, Democrats said on Tuesday in a report that lawmakers will use as the basis of any formal impeachment charges.

In the 300-page report, Democrats leading the House of Representatives Intelligence Committee leveled allegations of sweeping abuse of power by Trump, saying he used U.S. military aid and the prospect of a White House visit to pressure Ukrainian President Volodymyr Zelenskiy to undertake investigations that would benefit Trump politically.

Republican Trump, who will stand for re-election in November 2020, denies any wrongdoing and calls the inquiry a hoax.

The heart of the impeachment probe is whether Trump misused the power of his office to pressure Ukraine to investigate the son of former Vice President Joe Biden, a leading contender for the Democratic nomination to face Trump in the 2020 election.