Donald Trump has defended himself on Twitter as his administration faces an extraordinary showdown with Congress after acting national intelligence director Joseph Maguire withheld a whistleblower’s complaint understood to concern a private conversation between the president and a foreign leader, despite its being classified a matter of “urgent concern”.He also told reporters that they should “look into Joe Biden” when asked about the whistleblower’s complaint, in an angry press conference in the Oval Office, during which he called the whistleblower “bipartisan,” though he said he did not know who the person was.