The 12 GOP figures join 140 members in House who say they will object to certification of results

Mike Pence has said he welcomes an attempt by Republican senators to overturn the US election.
Ted Cruz is among 12 GOP senators who say they are preparing to challenge the results of the election in a joint session of Congress next week.
The Texas representative leads a group of 11 politicians who say they will not certify the election results unless there is a 10-day emergency audit of the results, in support of Donald Trump. Separately, Josh Hawley of Missouri plans his own challenge.
The outgoing president has refused to concede the election and made a string of false and debunked claims about election fraud in battleground states.
These false claims have been rejected by judges across the country, and Mr Trump and his backers have not provided any evidence to back their many discredited lawsuits. The election results have been ratified by every state and the former head of the federal governments cyber security unit described it as the most secure poll in US history. 
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Vice president Pence shares the concerns of millions of Americans about voter fraud and irregularities in the last election,” said Mr Pences chief of staff Marc Short in a statement hours after Mr Cruz announced his groups intentions.
The vice president welcomes the efforts of members of the House and Senate to use the authority they have under the law to raise objections and bring forward evidence before the Congress and the American people on 6 January.
Mr Cruz is being joined by Ron Johnson, James Lankford, Steve Daines, John Kennedy,  Marsha Blackburn, Mike Braun, as well as Senators-elect Cynthia Lummis, Roger Marshall, Bill Hagerty, and Tommy Tuberville.
Together the 11 senators claimed, without providing new evidence, that the election featured unprecedented allegations of voter fraud and illegal conduct.  Mr Trump tweeted approvingly in response, writing: Our country will love them for it! #StopTheSteal.
Members of the House of Representatives and the US Senate will meet in joint session at 1pm ET on 6 January in the House Chamber.
Mr Pence will preside in his role as president of the Senate and leaders of both parties will appoint lawmakers from both chambers to act as tellers.
Mr Pence will open certificates of the electoral vote from each state and they are handed to the tellers.
Any objection to the vote must be made in writing and endorsed by at least one member of the House and Senate.
Debate on any objection is limited to two hours and a majority vote is required in each chamber to uphold the objection and throw out the states votes.
If that is not achieved the objection is disposed of and the electoral votes are counted as cast.
Mr Cruz has become an outspoken supporter of Mr Trump, despite their public clashes since 2016. Mr Trump infamously questioned the attractiveness of Mr Cruzs wife, Heidi, on Twitter, and even once asked if the senators father was involved in the Kennedy assassination.
As many as 140 House Republicans are expected to also object to the election results. It is unlikely to make any difference to the outcome, as Joe Bidens win is almost guaranteed to be certified by majorities in the Democratic House and Republican Senate.
Observers say that the move is the first effort by potential 2024 Republican presidential candidates to position themselves and win approval from Mr Trump, if he decides against running for the White House again.
Pennsylvanias Republican senator, Pat Toomey, has criticised his GOP colleagues. The senators justify their intent by observing that there have been many allegations of fraud. But allegations of fraud by a losing campaign cannot justify overturning an election,” said Mr Toomey.
Senator Mitt Romney was similarly displeased, saying in a statement: The egregious ploy to reject electors may enhance the political ambition of some, but dangerously threatens our democratic republic.
“The congressional power to reject electors is reserved for the most extreme and unusual circumstances. These are far from it. More Americans participated in this election than ever before, and they made their choice. 
“President Trumps lawyers made their case before scores of courts; in every instance, they failed. The Justice Department found no evidence of irregularity sufficient to overturn the election. 
The Presidential Voter Fraud Commission disbanded without finding such evidence.
Senator Lisa Murkowski, from Alaska, also said she would vote to back the results of the 2020 election, adding: The courts and state legislatures have all honored their duty to hear legal allegations and have found nothing to warrant overturning the results.
“I urge my colleagues from both parties to recognize this and to join me in maintaining confidence in the electoral college and our elections.”