This smells very fishy or bullshitty.... Cynthia

Jake "Al-Qaeda is on our side in Syria" Sullivan, announced that he will personally conduct a briefing for the leaders of the US Congress on a certain "national security threat" on Thursday but refused to specify the information.
Earlier, the head of the House Intelligence Committee urged Biden to declassify all information about the "national security threat," the details of which have not been disclosed.

adding..

The US Congress was warned about a “foreign threat,” NBC News reported.

“A Democratic source familiar with the warning said that this is a “serious problem that could lead to a destabilizing situation and a threat to national security,” the channel reports.

According to a CNN source, the “threat” may be associated with certain “Russian capabilities.”

adding more found...

The threat to US national security, which was announced today in Congress and the White House, is associated with the Russian desire to send nuclear weapons into space.

This was reported by a number of American media outlets, citing “sources familiar with the discussions.”

It is reported that this is not about dropping nuclear weapons on Earth, but rather about their possible use against satellites.

“It’s very concerning and very sensitive,” said one source, who called it a “big deal.”

Many members of Congress called the problem serious, but not one that would cause public alarm.