![](https://focus.independent.ie/thumbor/qev_Prrxd4kceSq7xpNV7kV1tos=/0x0:3238x2158/960x640/prod-mh-ireland/ac6a51c2-b141-4ee6-b887-eaa041ce3598/4391c4b1-6433-464a-b187-99149c63c194/US%20HunterB%20%285%29.jpg )
US president Joe Biden&s son Hunter defied an order by Republicans in the US Congress to testify behind closed doors about his business dealings yesterday, ratcheting up tensions with lawmakers before a vote to formalise their impeachment probe of his father.