A bipartisan group of four senators is calling for a select committee to investigate Russian interference in the 2016 election.

Incoming Senate Minority Leader Charles E. Schumer of New York, Armed Services Chairman John McCain of Arizona, Armed Services ranking member Jack Reed of Rhode Island, and Sen. Lindsey Graham of South Carolina said Sunday that the Senate should establish a temporary committee to investigate the matter. The new committee would also develop comprehensive recommendations to improve cybersecurity.

“We share your respect for, and deference to, the regular order of the Senate, and we recognize that this is an extraordinary request,” the senators wrote in a letter to Senate Majority Leader Mitch McConnell. “However, we believe it is justified by the extraordinary scope and scale of the cyber problem. Democrats and Republicans must work together, and across the jurisdictional lines of the Congress, to address this unique challenge.”

Schumer and Reed are Democrats. McCain and Graham are Republicans.

The four senators called on Dec. 11 for an investigation into the issue, following a Washington Post report on the CIA’s assessment that the Russian hacking of the emails of the Democratic National Committee and Hillary Clinton’s campaign chairman was perpetrated to swing the election in favor of Donald Trump, now the president-elect. Trump has rejected the intelligence community’s conclusions.