US lawmakers have certified President-elect Joe Biden’s election win, defying a violent pro-Trump mob that attacked the Capitol in a bid to prevent a transfer of power.

The formal confirmation of Biden’s victory came after the count in Congress of Electoral College votes passed the 270 mark.

The joint session of Congress had been abruptly halted hours earlier after the rioters breached both chambers of the Capitol Building, forcing lawmakers to flee and hunker down until the siege ended.

After the House and Senate reconvened, Senate Majority Leader Mitch McConnell condemned the ransacking of the Capitol as a “failed insurrection.”

“They tried to disrupt our democracy. They failed. They failed. They failed to attempt to obstruct the Congress,” the top Senate Republican said.

The certification process was also met by lengthy delays thanks to a handful of Republicans who put forward objections to the counting of votes in states won by Biden. The challenges were rejected.

After Congress certified President-elect Joe Biden’s win, US President Donald Trump promised an “orderly” transfer of power on Jan. 20.

“Even though I totally disagree with the outcome of the election, and the facts bear me out, nevertheless there will be an orderly transition on January 20th,” Trump said early Thursday as he continued to promote debunked claims of voter fraud.

The statement was issued via Trump’s social media director Dan Scavino as the president’s personal Twitter account was locked following the attack on the US Capitol by his loyalists on Wednesday.

“While this represents the end of the greatest first term in presidential history, it’s only the beginning of our fight to Make America Great Again!” the statement ended.

Trump’s term is set to expire at noon, Eastern Standard Time, on Jan. 20.