Washington: An apparent chance meeting between former president Bill Clinton and US Attorney General Loretta Lynch made waves Thursday in Washington, as White House hopeful Hillary Clinton’s email usage remained under investigation.

The Monday meeting came a day before Republican lawmakers released their final report on the 2012 assault on the US mission in Benghazi, and as Hillary Clinton’s campaign faces continued questions about her trustworthiness.

The encounter raised concern about whether the independence of the Department of Justice, which is led by Lynch and is conducting an investigation into the emails, has been compromised.

Lynch said the meeting at the airport in Phoenix, Arizona was purely coincidental and stressed that the conversation did not touch on any cases for which her office is responsible.

‘There was no discussion of any matter pending for the department or any matter pending for any other body,’ she said, according to US media.

‘There was no discussion of Benghazi, no discussion of the State Department emails, by way of example.’

Clinton’s use of a private email account and home server while secretary of state between 2009 and 2013 has weighed on her campaign for a year and served as a preferred line of attack by her political opponents.

‘That’s terrible,’ presumptive Republican presidential nominee Donald Trump said on the Mike Gallagher radio show, speaking of the meeting.

‘It was really something that they didn’t want publicised.’

White House press secretary Josh Earnest said Lynch and President Barack Obama ‘understand how important it is for the Department of Justice to conduct investigations that are free of political interference.’

But he declined to say whether the meeting should not have occurred, or if he thought it suggested a conflict of interest months before the election.

The optics left some critics and observers stunned.

‘This incident does nothing to instil confidence in the American people that her department can fully and fairly conduct this investigation,’ said number two Senate Republican John Cornyn as he repeated his call for a special prosecutor to oversee the Clinton emails investigation.

On Twitter, former Obama advisor David Axelrod said he believed no improper conversation took place, but added that it was ‘foolish to create such optics.’