Outgoing Senate Majority Leader Mitch McConnell blamed President Donald Trump for encouraging the fatal riot at the U.S. Capitol earlier this month as his supporters attempted to overturn the election results.

"They were provoked by the president and other powerful people and they tried to use fear and violence to stop a specific proceeding [...] which they did not like," the senator said, addressing his colleagues in the early hours of Wednesday Hong Kong-time.

After four years of toeing the party line for Trump, Republican McConnell, who will become minority leader in the new Congress after the inauguration, fingered the outgoing president for encouraging his supporters to storm the Capitol on Jan. 6, joining his colleague and soon to majority leader, Chuck Schumer.

"We need to set a precedent that the severest offense ever committed by a president will be met by the severest remedy provided in the Constitution," Democratic Senator Schumer said.

President-elect Joe Biden and vice president-Elect Kamala Harris will have a "safe and successful" inauguration on Wednesday, McConnell promised.

Calls for unity and stability on both sides of the aisle have dominated the final days of Trump's presidency. The businessman-turned-politician was impeached for a second time last week for inciting the violence in Washington that left five dead and many injured.

House Speaker Nancy Pelosi will wait until after Biden's inauguration to send the article of impeachment, which will spark the Senate trial of Trump. McConnell has not yet shared whether he will vote for or against the charges.

Federal authorities are now pouring over hours of footage taken during the Jan. 6 riot to identify suspects. More than 100 participants, including an elected official from New Mexico, have already been charged.

But political and social divisions continue to fester across the country, not least in Washington, D.C., where power has not been split between the parties so evenly since 2001.

Three new Democratic senators will be sworn into office on Wednesday, ending nine years of Republican majority in the upper chamber of Congress, and leaving vice president Harris to provide the tie-breaking vote in the now 50-50 split Senate.

"Americans elected a closely divided Senate, a closely divided House and a presidential candidate who said he'd represent everyone," McConnell said, summing up the impossible challenge Biden now faces.