The State Department on Tuesday blocked a top US diplomat from speaking to Congress as part of Democratic lawmakers’ impeachment investigation of President Donald Trump.

Ambassador to the European Union Gordon Sondland had previously agreed to be deposed, but “early this morning, the US Department of State directed (him) not to appear today for his scheduled transcribed interview,” Sondland’s lawyer Robert Luskin said in a statement.

The move escalates the confrontation between the White House and congressional Democrats investigating the president for possible impeachable offenses including obstruction of justice. (AFP)