The decision by House and Senate leaders on Monday to push for congressional investigations into possible Russian interference of the U.S. election puts Donald Trump's administration at odds with fellow Republicans before he takes office.

Both Senate Majority Leader Mitch McConnell and House Speaker Paul Ryan backed inquiries into the findings of American intelligence agencies that Russian cyberattacks attempted to influence the American vote.

"As I've said before, any foreign intervention in our elections is entirely unacceptable," said Ryan in a statement. "And any intervention by Russia is especially problematic because, under President Putin, Russia has been an aggressor that consistently undermines American interests."

McConnell told reporters that an investigation led by Sens. Richard Burr and john McCain would delve into the allegations. He said that lawmakers "need to approach all these on the assumption the Russians do not wish us well."

Aides to U.S. Sens. Johnny Isakson and David Perdue had no immediate comment on whether the Republicans backed the inquiries.

Trump and his deputies have lashed out at reports contending that Putin and other Russian authorities tried to damage Democrat Hillary Clinton's campaign to boost Trump.

"It could be Russia and it could be China," he told Time Magazine in a recent interview. "And it could be some guy in his home in New Jersey."

Meanwhile, Clinton's campaign for the first time publicly backed a push by a group of electors for a briefing by intelligence agencies on possible foreign interference of the election. Electors, including the 16 in Georgia, are set to formally cast their votes on Monday amid a push from Trump's critics to defy the president-elect.

"The bipartisan electors' letter raises very grave issues involving our national security," Podesta said in a statement Monday to Politico. "Electors have a solemn responsibility under the Constitution and we support their efforts to have their questions addressed."

The congressional pushback comes amid increasing scrutiny of Rex Tillerson, the ExxonMobil chief executive said to be Trump's top pick for secretary of state. Several U.S. senators have questioned his close ties to Russia, raising the specter of a tough confirmation fight next month if Tillerson is tapped.