Washington | The Senate impeachment trial on whether to remove US President Donald Trump from office formally began on Thursday (Friday AEDT) even as a congressional watchdog found that the White House broke the law by withholding security aid for Ukraine approved by Congress.

The assessment from the non-partisan Government Accountability Office (GAO) was a setback for Trump, but it was unclear if it would figure in his trial in the Republican-led Senate given that key questions such as whether witnesses will testify or new evidence will be considered remain unanswered.

Reuters