The Secret Service disputed that accusation on Thursday, saying some phone data was lost during a routine device migration, but that all of the requested texts had been saved.

In a letter to the House of Representatives and Senate Homeland Security Committees investigating the events of 6 January 2021, the Department of Homeland Security (DHS) inspector general’s office (OIG) said “many” messages had been erased by the Secret Service with a device-replacement program after the watchdog asked for the records.

It was not clear from the letter what messages the inspector general’s office believed had been deleted or what evidence they might contain.

After the letter was published on Thursday, Bennie Thompson, who chairs both the congressional panel probing the Capitol attack and the House Homeland Security Committee, told the Axios news website the alleged deletion was “concerning”.

“If there’s a way we can reconstruct the texts or what have you, we will,” Thompson said.

The DHS did not respond to a request for comment late on Thursday.

In a lengthy statement issued in response to the accusations, a Secret Service spokesman said the agency had “fully” cooperated with the inspector general’s office.

“DHS OIG requested electronic communications for the first time on February 26, 2021, after the migration was well under way,” spokesman Anthony Guglielmi said. “The Secret Service notified DHS OIG of the loss of certain phones’ data, but confirmed to OIG that none of the texts it was seeking had been lost in the migration.”

Guglielmi said that despite the assertions of the inspector general’s office, its employees had been granted “appropriate and timely access” to the materials.

The attack on the US Capitol followed weeks of false claims by Trump that he won the 2020 election. On Tuesday, lawmakers of the House panel probing the attack accused Trump of inciting the violence in a last-ditch bid to remain in power after losing the election.