Donald Trump's senior adviser and son-in-law, Jared Kushner, reportedly urged a top executive at CNN's parent company to fire a fifth of its staff over its coverage of the presidential election.

Mr Kushner told Time Warner executive Gary Ginsberg that the broadcaster should sack 20 per cent of its employees because their analysis of the outcome of the November's vote had been wrong, according to the Wall Street Journal.

A White House official claimed Mr Kushner had been joking but sources at the media company told the newspaper the remark "wasn't taken lightly".

Mr Ginsberg reportedly replied that Time Warner would not be able to sack CNN staff and would not consider doing so.

President Trump has frequently lashed out at CNN over its coverage of him and his administration, disparaging it and its reporters as "fake news".

Mr Kushner's reported comments emerged as the US government holds up an acquisition of Time Warner by American telecoms giant AT&T.

His remarks will ​fuel suspicion that the Justice Department has put the brakes on the $85 billion (£65 million) deal so the White House can put pressure on CNN.

The Justice Department has reportedly told AT&T that it wants the telecoms company to ditch video assets, citing competition laws. The government is said to have made the sale of the DirecTV satellite unit or Time Warner's Turner Broadcasting, which houses CNN, a condition of approval.

Trump renews attack on media with video showing him 'beating up CNN'

As a candidate, Mr Trump vowed to block the merger because it concentrated too much "power in the hands of too few."

But the hold-up has raised suspicions of political retaliation even among those who oppose the deal.

"While there are plenty of good reasons to oppose AT&T's Time Warner takeover, punishing CNN for trying to hold this administration accountable isn't one of them," said Craig Aaron, president of Free Press. The consumer group opposes the deal and media consolidation in general.

Jessica Rosenworcel, a Democratic member of the Federal Communications Commission, tweeted: "Are we really going to make the [Justice Department] use anti-trust law to force the sale of a cable channel because the President doesn't like its news coverage?

"You can dislike consolidation but still find this extremely disturbing if true."

A White House spokesman said Mr Trump "did not speak with the attorney general about this matter"