Donald Trump has said Russia never wanted him to become the US president and repeated his allegation that an investigation into whether his campaign team colluded with Moscow is a "witch hunt".

He made the comment while tweeting a story by Fox News which reported claims that the company behind the infamous Trump dossier also worked "on behalf of the Russian state."

Trump tweeted on Saturday (29 July): "In other words, Russia was against Trump in the 2016 Election – and why not, I want strong military & low oil prices. Witch Hunt!"

The US President has previously said Russian leadership would have preferred his Democratic rival Hillary Clinton to win last year's election.

The Trump dossier, compiled by former British spy Christopher Steele, contains unsubstantiated claims concerning compromising information that Moscow allegedly has on the billionaire businessman.

Steele was hired by the company Fusion GPS to create the dossier during the 2016 presidential campaign.

On Thursday (27 July), a Senate committee heard testimony from financier Bill Browder, CEO of Hermitage Capital, who claimed the firm had also previously been hired to do the bidding of the Russian government.

Browder said Fusion GPS co-founder Glenn Simpson was paid money "to conduct a smear campaign" against him in a bid to fight proposed US sanctions against Russian figures.

Browder testified that Simpson was hired to stop the passing of the 2012 Magnitsky Act by Natalia Veselnitskaya – the same Russian lawyer who sought a Trump Tower meeting last June with Donald Trump Jr., Jared Kushner and then-Trump campaign chairman Paul Manafort.

At the time of the alleged smear campaign against Browder, Veselnitskaya was said by him to be part of a group acting on behalf of the Russian state.

The White House spoke out against the dossier this week, pointing out the alleged link between Russia and Fusion GPS.

"Today, there was public testimony that further discredited the phony dossier that's been the source of so much of the fake news and conspiracy theories, and we learned that the firm that produced it was also being paid by the Russians," White House Press Secretary Sarah Huckabee Sanders said in a press briefing.

Fusion GPS later denied spreading false information about Browder. "What is clear is that the president and his allies are desperately trying to smear Fusion GPS because it investigated Donald Trump's ties to Russia," it said.