The Justice Department has started to recover missing text messages between two FBI officials who expressed an anti-Trump bias, according to Fox News.

The news comes one day after Attorney General Jeff Sessions ordered an investigation into the missing text messages.

Texts between FBI agent Peter Strzok and FBI lawyer Lisa Page exchanged between Dec. 14, 2016, and May 17, 2017, are among a broader batch of missing phone messages that the FBI says its system failed to store because of a software upgrade glitch on many Samsung 5 cellphones.

The White House called them evidence of potential illegality at a briefing on Tuesday, and said the president believes it is of 'great cause for concern'.

Trump earlier tweeted they were 'one of the biggest stories in a long time'.

Republicans have said the texts, which referred to Trump as an 'idiot' and a 'loathsome human,' raise concerns the FBI is biased against Trump and may have given Hillary Clinton, his Democratic presidential rival, favorable treatment after deciding not to recommend criminal charges in connection with the investigation of her use of a private email system while she was secretary of state.

Strzok and Page were involved in that investigation and were briefly assigned to work with Special Counsel Robert Mueller on the investigation of Russian meddling in the 2016 presidential election.

The Justice Department has started to recover missing text messages between two FBI officials who expressed an anti-Trump bias, according to Fox News host Sean Hannity

The White House said Tuesday that a trove of missing messages between two FBI officials who were caught deriding the president before the election may point to 'possibly illegal behavior' and the president believes it is of 'great cause for concern

Attorney General Jeff Sessions ordered officials in the Department of Justice to 'leave no stone unturned' in their search for the 50,000 missing texts between the FBI agent and his lawyer lover

The Justice Department last week revealed a critical gap in messages between Peter Strzok, a counterintelligence agent who worked on Hillary Clinton's email case, and Lisa Page, an agent who worked with Strzok for a time on the special counsel investigation into Russian election interference

President Donald Trump put the spotlight back on the FBI agents he'd previously accused of 'treason' in an early-morning tweet

Reports said the texts between them were exchanged on FBI-issued phones during the course of an alleged extramarital affair.

Mueller was appointed on May 17, the same day when some of the text messages were not properly stored.

'We will leave no stone unturned to confirm with certainty why these text messages are not now available to be produced and will use every technology available to determine whether the missing messages are recoverable from another source,' Sessions said in a statement.

President Donald Trump put the spotlight back on the FBI agents he'd previously accused of 'treason' in an early-morning tweet.

'In one of the biggest stories in a long time, the FBI now says it is missing five months worth of lovers Strzok-Page texts, perhaps 50,000, and all in prime time. Wow!' he said.

His press secretary stepped up the assault later, at her daily briefing, after she was asked if the White House believes that the missing messages are part of a cover-up.

'I think he thinks that there's a great cause for concern that five months worth of text messages have gone missing,' Sarah Sanders said, 'particularly given the individual had part of that process has already been shown to be extremely biased against the president and was involved in what seems to be some very inappropriate behavior and that's certainly a great concern.'

Sanders said it 'looks like there could be some really inappropriate and possibly illegal behavior' at play.

The Justice Department last week revealed a critical gap in messages between Peter Strzok, a counterintelligence agent who worked on Hillary Clinton's email case, and Lisa Page, an agent who worked with Strzok for a time on the special counsel investigation into Russian election interference.

Texts the pair sent each other between December 14, 2017 and May 17, 2017 are missing, the department informed Congress.

Justice has blamed a glitch in its record-keeping system for the blackout.

Attorney General Jeff Sessions said that Justice is taking all available actions to recover the missing messages.

Not including the missing communications, Fox News reported, the FBI has over 50,000 texts that Strzok, who was removed from special counsel Robert Mueller's team when the original messages were unearthed, and Page, who had already left the investigation, sent to one another.

The messages are expected to be made public by Congress, CBS reported.

Previously published texts show Strzok suggesting the bureau invest in an 'insurance policy' in case Trump is elected.

'I want to believe the path you threw out for consideration...that there's no way he gets elected—but I'm afraid we can't take that risk. It's like an insurance policy in the unlikely event you die before you're 40,' he told Page in an August 2016 text.

Lawmakers said Monday that they were shocked by the incomplete record-keeping. The messages from the period of time that was wiped covers the end of the transition to the time that Mueller was tasked with leading a special probe into Russian meddling in the 2016 election.

House Oversight Committee Chairman Trey Gowdy told Fox News yesterday evening that an exchange between Strzok and Page the day after the election said, ''Perhaps this is the first meeting of the secret society.''

'So, of course I'm going to want to know: What 'secret society' are you talking about?' the Republican congressman said on 'The Story with Martha MacCallum.'

A letter from Assistant Attorney General for Legislative Affairs Stephen Boyd to Senate Homeland Security Committee Chairman Ron Johnson on Friday said that the Department of Justice had learned 'that many FBI-provided Samsung 5 mobile devices did not capture or store text messages.'

The bureau told DOJ that messages were not retained 'due to misconfiguration issues related to rollouts, provisioning, and software upgrades that conflicted with the FBI's collection capabilities.'

DOJ's explanation of how the messages disappeared had Republican lawmakers fuming.

His press secretary stepped up the assault later, at her daily briefing, after she was asked if the White House believes that the missing messages are part of a cover-up. 'I think he thinks that there's a great cause for concern that five months worth of text messages have gone missing,' Sarah Sanders said

'Unreal. We've been asking for the remaining text messages between anti-Trump FBI agents (and former Mueller team members), Peter Strzok and Lisa Page. The FBI now says the texts are 'missing,' ' Rep. Mark Meadows, leader of a group of conservatives known as the House Freedom Caucus, tweeted. 'If it wasn't already clear we need a second special counsel, it's abundantly clear now'.

Flabbergasted, Meadows told Fox, 'They're supposed to be out tracking terrorism and we can't even find our own text messages?'

Sessions told congressional committees on Friday that the Department of Justice's Inspector General is looking into the matter.

'[A] review is already underway to ascertain what occurred and to determine if these records can be recovered in any other way,' he said. 'If any wrongdoing were to be found to have caused this gap, appropriate legal disciplinary action measures will be taken.'

Prior to the revelation that the FBI was missing the large volume of communications, President Trump had attacked Strzok and Page in a Wall Street Journal interview and accused them of 'treason' for the way they spoke about him before the election.

'There was no collusion on our side, the collusion was on the Democrat side with the Russians. And what went on with the FBI, where a man is tweeting to his lover that if she loses, we'll essentially go back to the - we'll go to the insurance policy, which is - if they lose, we'll go to phase two, and we'll get this guy out of office.

'I mean, this is the FBI we're talking about. I think that is—that is treason. See, that's treason right there,' he stated.

In December, after Strozk was removed from the special counsel probe because of the text messages, Trump said the FBI's reputation was in 'tatters' because of mismanagement under James Comey, the former director of the bureau the president fired in May.

'But fear not, we will bring it back to greatness,' he pledged.