Diplomats' text messages boost impeachment pressure on Trump

Text messages sent by US diplomats revealing an apparent effort by Donald Trump's government to push Ukraine to investigate his political rival Joe Biden bolstered the Democrats' impeachment inquiry Friday, as the president suggested he might not cooperate with the probe.

The investigation picked up steam as Democrats in the House of Representatives began interviewing a key US intelligence official on a whistleblower complaint that alleged abuse of office by the president.

Meanwhile, Senator Mitt Romney, perhaps the most prominent Republican critic of Trump, blasted what he called a "wrong and appalling" move by Trump to ask Beijing and Kiev to investigate Biden -- the latest small crack in support for the president within his own party.

Despite Romney's comments, Trump insisted that Republicans in the Senate will unite behind him, should the Democratic-led House of Representatives vote to impeach him, triggering a trial in the upper chamber.

"The Democrats -- unfortunately, they have the votes. They could vote very easily, even though many of them don't believe they should do it," Trump told reporters.

"I have a 95 per cent approval rating in the Republican Party," he said.

"We'll get it to the Senate and we'll win. The Republicans are unified."
"When the only American citizen President Trump singles out for China's investigation is his political opponent in the midst of the Democratic nomination process, it strains credulity to suggest that it is anything other than politically motivated."