WASHINGTON — (CNN) House Democrats are set to introduce legislation Wednesday calling for a formal probe into Russian cyber hacking in the 2016 election, part of a broader Democratic push to shed light on unprecedented foreign interference in a US voting season.

Leading national security Democrats in the House also asked the White House on Tuesday to share classified information on Russian hacking with Congress, saying in a letter that Moscow “may have succeeded in weakening American’s trust.”

“We are deeply concerned by Russian efforts to undermine, interfere with and even influence the outcome of our recent election,” said the letter, signed by Adam Schiff, the most senior Democrat on the House Permanent Select Committee on Intelligence, and six others. “By eroding Americans’ and foreigners’ trust in US institutions, Russia both weakens our country and sows global instability and uncertainty.”

The House legislation, to be announced Wednesday, according to California Rep. Eric Swalwell, a Democrat on the House Permanent Select Committee on Intelligence, is one of several Democratic efforts to shine a brighter light on Russia’s cyber activities. The initiatives could lead to a clash with Republicans and will almost certainly cause tension with the incoming administration.

President-elect Donald Trump has expressed admiration for Russian Prime Minister Vladimir Putin and a desire to work more closely with Moscow. During the campaign, Trump dismissed the assessment by all 17 US intelligence agencies that Russia was responsible for thefts and disclosures that were “intended to interfere with the US election process.”

Instead, Trump suggested the hacks could be the work of “someone sitting on their bed that weighs 400 pounds.”

In contrast, Putin and the Democratic candidate Hillary Clinton had a long history of mutual criticism and clashes. The hacked information, published through sites like WikiLeaks, was exclusively from Democratic organizations and individuals, including Clinton’s campaign chairman.

Now, the US intelligence community is increasingly confident that Russian meddling wasn’t just meant to roil the presidential election, but was explicitly intended to support Trump, CNN has reported, based on multiple sources.

The Russian Embassy did not respond to requests for comment.

The House Democrats’ letter to the White House Tuesday comes on top of an earlier letter sent by seven Senate Democrats that called for the Obama administration to publicly release information showing that the Russian interference was explicitly meant to help Trump.