More impeachment calls as ex-White House lawyer skips hearing

House Democrats have renewed calls for impeachment proceedings against President Donald Trump, after a former White House counsel failed to appear before Congress despite a subpoena.

Donald McGahn skipped a hearing on Tuesday about the Mueller report.

In an extraordinary move, President Trump has vowed to block all subpoenas of his current and former staff.

"Our subpoenas are not optional," said House Judiciary Committee chairman Jerry Nadler, after the failed hearing.

"Let me be clear: this committee will hear Mr McGahn's testimony, even if we have to go to court to secure it," he said.

The Trump administration claims that the report by Special Counsel Robert Mueller, into allegations of Russian collusion and obstruction of justice, cleared him of wrongdoing, and that there are no further questions to answer.

The administration also claims that staff cannot legally be compelled to testify, but Mr Nadler said he would hold Mr McGahn in contempt and pursue other means of compelling testimony.

"We will hold this president accountable, one way or the other," he said.

President Trump responded on Twitter on Tuesday, arguing that he had "allowed everyone to testify" to Robert Mueller's team, and accusing the Democrats of seeking a "do-over" of the special counsel investigation.