The leaders of the US Senate Intelligence Committee have jointly pledged their investigation of Russian hacking of the 2016 US election campaign would be bipartisan, a sharp contrast to bitter partisan disagreements surrounding a similar investigation in the House of Representatives.

Senator Richard Burr, the committee’s Republican chairman who served as a security adviser to President Donald Trump’s campaign, told reporters on Wednesday he has not coordinated with the White House on the scope of the investigation.

Burr declined to go along at this point with the White House’s denial of collusion between the Trump campaign and Russian hackers, who US intelligence officials believe sought to influence the election for the Republican Trump at the expense of his Democratic challenger, Hillary Clinton.

“We would be crazy to dry to draw conclusions from where we are in the investigation,” Burr said at a joint news conference with Senator Mark Warner, the top Democrat on the intelligence panel.

“Let us go a little deeper into this before you ask us to write the conclusions,” Burr said. “That’s clearly something we intend to do down the road.”

Both senators said their challenge is to answer for the American people whether there was anything in the investigation suggesting a direct link to Trump.

Warner and Burr both stressed the importance of exposing the activity of Russian hackers, which Warner said included about 1000 “paid Internet trolls” who spread false negative news reports about Clinton.

The two senators said they also wanted to publicise what they described as Russia’s attempts to influence upcoming elections in France and Germany.

Allegations by US intelligence agencies that Russian actors sought to boost Trump have lingered over Trump’s young presidency. Trump dismisses such assertions and Russia denies the allegations.