US Democrats have launched an investigation into President Donald Trump’s firing of the state department’s internal watchdog.

Inspector General Steve Linick was investigating Secretary of State Mike Pompeo for suspected abuse of office, reports say.

But he was sacked late on Friday after Mr Trump said he no longer commanded his full confidence.

The move prompted angry criticism from senior Democrats in Congress.

They accused Mr Trump of retaliating against public servants who want to hold his administration to account. Mr Linick was the third official responsible for monitoring government misconduct to be dismissed in recent weeks.

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The former prosecutor was appointed by Mr Trump’s predecessor, Barack Obama, to oversee spending and detect mismanagement at the state department.

On Saturday, top Democrats on the House and Senate Foreign Relations Committees questioned the timing of Mr Linick’s removal and announced an immediate investigation.

“We unalterably oppose the politically-motivated firing of inspectors general and the president’s gutting of these critical positions,” Congressman Eliot Engel and Senator Bob Menendez said in a statement.

They said Mr Linick had “opened an investigation into wrongdoing by Secretary Pompeo himself”, adding that his firing was “transparently designed to protect Secretary Pompeo from personal accountability”.

Mr Linick had begun investigating allegations that Mr Pompeo had improperly used staff to run personal errands, US media report.