WASHINGTON (AFP) - In the latest in a series of broadsides against the media, US President Donald Trump suggested on Thursday (Oct 5) that lawmakers investigate journalists for their work.

"Why Isn't the Senate Intel Committee looking into the Fake News Networks in OUR country to see why so much of our news is just made up-FAKE!" Trump said in a tweet.

That was a reference to a Senate panel which on Wednesday said it was still investigating collusion between Trump's 2016 presidential campaign and Moscow.

Trump has long railed against what he sees as unfair press coverage and used attacks on the media to rally supporters.

The latest fit of pique was prompted by an NBC News report that Secretary of State Rex Tillerson had considered resigning from the administration earlier this year and openly referred to Trump as a "moron".

"Rex Tillerson never threatened to resign. This is Fake News put out by @NBCNews. Low news and reporting standards. No verification from me," he tweeted.