Donald Trump’s supporters have launched a scathing attack on a Fox News anchor who criticised the US President’s treatment of reporters and his refusal to answer questions at his first solo press conference.

Shepard Smith accused Mr Trump of "repeating ridiculous, throwaway lines that are not true at all."

He said: "It's crazy what we're watching every day. It's absolutely crazy."

His comments came after the US President launched a sustained attack on the media during a fiery and, at times chaotic, news conference.

The former real-estate mogul accused the press of deliberately misleading the public over his administration's ties to Russia, after intelligence leaks suggested his campaign aides had been in close contact with the country.

Mr Trump's national security adviser Michael Flynn was also forced to resign when it was revealed he attempted to cover up conversations he had with the Russian ambassador, Sergey Kislyak, about the issue of sanctions, before taking up the post.

It is illegal for a private citizen to conduct diplomacy on behalf of the US.

Mr Smith, who joined the Fox News Channel at its inception in 1996, insisted the American people deserved to know the truth about any “improper communications with Russian officials”.

He also defended CNN journalist Jim Acosta as an “accomplished reporter" after Mr Trump said said he was upgrading the broadcaster from “fake news” to “very fake news.”

But supporters of the Republican leader took to Twitter to vent their fury at Mr Smith’s comments, accusing him of breaking with the channel's editorial line.

Many threatened to boycott Fox News, historically one of few mainstream media sources to have backed Mr Trump during his election campaign.

Mr Smith had urged Mr Trump to tell the truth over allegations his campaign aides had close contact with Russia during the presidential race.

"He keeps repeating ridiculous throwaway lines that are not true at all and sort of avoiding this issue of Russia as if we're some kind of fools for asking the question," he said.

"Your opposition was hacked and the Russians were responsible for it and your people were on the phone with Russia on the same day it was happening and we're fools for asking the questions?"

Mr Trump was repeatedly questioned by reporters over the allegations at the press conference but he maintained his position that the “news is fake.”

“The leaks are absolutely real. The news is fake because so much of the news is fake,” he said. "Russia is fake news. Russia — this is fake news put out by the media.”

However Mr Smith hit back at the former real-estate mogul’s denial saying “we have a right to know.”

“You owe this to the American people. Your supporters will support you either way. If your people were on the phone, what were they saying?” he said.