Adam Smith, the chairman of the committee, told defence officials that QAnon conspiracy theorists and Trump supporters were considering another siege on the Capitol on that day.
QAnon conspiracists — borrowing claims made by the extremist sovereign citizens movement — believe that Mr Trump will come back as US president on 4 March, the day inaugurations took place before 1933.
According to bizarre theories circulating online, the United States has not been a country since the gold standard was unpegged in 1933 under Franklin D Roosevelt, while no president has been legitimate since a certain law was passed in 1871 under Ulysses S. Grant.
Mr Smith told defence officials, “they are thinking maybe we should gather again and storm the Capitol on March 4, that is circulating online”.
“Stuff like that circulates all the time, does it mean it’s going to happen, probably not,” said Mr Smith, “but if you want to help, tell them not to do that, tell them that the election is over. Joe Biden won.”
Concerns about QAnon and Trump supporters planning another attack on 4 March have been circulating for weeks, as Julian Feeld, producer of the QAnon Anonymous podcast that debunks QAnon theories, told CNN.
“I think there is obviously different beliefs about what will happen on that day, but I think many people are expecting a ceremony, and that ceremony might be accompanied in their mind by what QAnon believers call ‘the storm’”, said Mr Feeld.
“That would be the rounding up, or military tribunals, you know for leading Democrats and some celebrities they believe, falsely, to be part of this secret paedophile cabal. So essentially people are still in this belief that Trump will come back, and will become the president again.”
The meeting between Congressional lawmakers and defence officials comes after the Pentagon and US Capitol Police were both criticised for their response to the 6 January attack on Congress, which left at least five people dead.