US prosecutors say Jack Teixeira, the airman charged with leaking secret military information, may still have access to classified material.
They said he should remain in jail pre-trial as he could cause “extraordinary” damage to national security.
Prosecutors will make their case to a judge at a hearing on Thursday.
Investigators are still working to determine how Mr Teixeira allegedly leaked dozens of files and whether he kept any physical or digital copies.
The documents, which first appeared in the online chat room Discord, included sensitive information about US allies and the war in Ukraine.
Mr Teixeira’s legal team have not commented on the case. They are expected to argue the 21-year-old should not be detained before trial.
In a 48-page court filing on Wednesday, the justice department outlined their argument for keeping Mr Teixeira behind bars.
“There simply is no condition or combination of conditions that can ensure the defendant will not further disclose additional information still in his knowledge or possession,” prosecutors wrote.
“The damage the defendant has already caused to the US national security is immense. The damage the defendant is still capable of causing is extraordinary.”
In the filing, prosecutors said Mr Teixeira had accessed large amounts of sensitive information which “far exceeds what has been publicly disclosed”.
Prosecutors also said that, after his arrest, the FBI found a tablet, a laptop and an Xbox gaming console at his home that had been smashed and placed in a dumpster.
They also alleged Mr Teixeira had a history of making violent threats. He discussed violence and murder on Discord and was also prone to making “racial threats” on the platform, the prosecutors wrote.
Meanwhile, two commanders at Mr Teixeira’s unit, the 102nd Intelligence Support Squadron in Massachusetts, have been put on leave pending an investigation.
They have temporarily lost access to classified systems and information, the US Air Force said in a statement. Their names have not been released.
The Air Force told the BBC’s US news partner CBS that more members of Mr Teixeira’s unit could face suspension or removal as the investigation into the leaked documents continued.
The unit was relieved of its intelligence-gathering duties earlier this month.
The leaked intelligence material first appeared in a Discord chat room, which Mr Teixeira is said to have helped administer.
The documents were then shared outside the chat room by some of its members, the FBI said.
The agency earlier said Mr Teixeira held “top secret” security clearance since 2021, and that he would have “signed a lifetime binding non-disclosure agreement” to take on his role in the US Air Force.
Mr Teixeira faces up to 25 years in prison over charges of unauthorised transmission of defence information.
He is also charged with the unauthorised removal and retention of classified documents.
