Washington: A growing number of congressional Republicans expressed exasperation on Friday over what they view as President Donald Trump's indefensible behaviour, a sign that the president's stranglehold on his party is starting to weaken as Congress hurtles toward a historic impeachment vote.

Senate Majority Leader Mitch McConnell. Credit:Bloomberg

In interviews with more than 20 GOP lawmakers and congressional aides in the past 48 hours, many said they were repulsed by Trump's decision to host an international summit at his own resort and incensed by acting White House chief of staff Mick Mulvaney's admission - later withdrawn - that US aid to Ukraine was withheld for political reasons.

Others expressed anger over the president's abandonment of Kurdish allies in Syria.

One Republican, Representative Francis Rooney of Florida - whose district Trump carried by 22 percentage points - did not rule out voting to impeach the president and compared the situation to the Watergate scandal that ended Richard Nixon's presidency.