Forty members of the Electoral College on Tuesday signed a letter demanding an intelligence briefing on Russian interference in the election ahead of their Dec. 19 vote.

Ten electors originally signed the letter when it was published Monday, and 30 more have since added their names.

The open letter — led by Christine Pelosi, the daughter of House Democratic Leader Nancy Pelosi (Calif.) — urged Director of National Intelligence James Clapper to give a detailed briefing on President-elect Donald Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE's ties to Russia.

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“We further require a briefing on all investigative findings, as these matters directly impact the core factors in our deliberations of whether Mr. Trump is fit to serve as President of the United States,” the letter read.

The Clinton campaign applauded the effort Monday, saying it had repeatedly warned about Russian interference aimed at swaying the election in Trump’s favor.

“Despite our protestations, this matter did not receive the attention it deserved by the media in the campaign,” Clinton campaign chairman John Podesta said in a statement. “We now know that the CIA has determined Russia's interference in our elections was for the purpose of electing Donald Trump. This should distress every American.”

The signees of the letter are all Democratic electors, aside from one Republican: Chris Suprun from Texas.

Suprun has already pledged not to vote for Trump, and claimed last week that other Republican electors plan to pick an alternative, too.

Bipartisan efforts in Congress are underway to investigate the CIA’s conclusion that Russian interference swayed the election in Trump’s favor.

Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellFEC flags McConnell campaign over suspected accounting errors Poll: 59 percent think president elected in November should name next Supreme Court justice Mark Kelly: Arizona Senate race winner should be sworn in 'promptly' MORE (R-Ky.) on Monday said the Senate Intelligence Committee should investigate the findings.

“We’re going to follow the regular order,” he said. “It’s an important subject and we intend to review it on a bipartisan basis.”