On Pentagon leak, White House officials say much remains to be known

April 10 (UPI) -- White House officials are unclear where the leak of sensitive Pentagon documents is coming from or if it has been contained.

The Pentagon is working "around the clock" to determine the true gravity of the leaks, including where the documents have been leaked to, Chris Meagher, assistant to the secretary of defense for public affairs, said Monday, according to The Hill.

"We're still investigating how this happened, as well as the scope of the issue. There have been steps to take a closer look at how this type of information is distributed and to whom," Meagher said. "We're also still trying to assess what might be out there."

Meagher added that Defense Secretary Lloyd Austin was briefed on the leaks on Thursday. Austin and several Pentagon officials then began working to uncover more information.

Documents relating to Iran's nuclear program, North Korea's missile program, support of Israel against the Islamic State and details about the war in Ukraine have appeared on the social media site Discord in recent weeks. The Department of Defense has confirmed the validity of the documents, though clarifying that documents appear to be edited.

The documents, marked classified, are believed to have been created between mid-February and early March, according to CNN. A spokesperson for Discord said the company is cooperating with an investigation into the incident.

U.S. allies such as Ukraine have weighed in on some of the documents. Mykhailo Podolyak, adviser to Ukrainian President Volodymyr Zelensky, questioned the authenticity of the documents, saying they are based on ""a large amount of fictitious information."

In a press briefing Monday, National Security Council Coordinator for Strategic Communications John Kirby said President Joe Biden has been continually briefed on the situation in recent days.

"The Department of Defense has referred this to the Department of Justice for a criminal investigation," Kirby said. "I am not aware that they have come to any conclusions at this point about where they are coming from."

Whether the leaks are an "ongoing threat," Kirby said, "We don't know."