"I am requesting that President Biden declassify all information relating to this threat so that Congress, the Administration, and our allies can openly discuss the actions necessary to respond to this threat," Representative Mike Turner said in the statement.

He provided no further information, and his office did not immediately respond to requests for further comment.

Two sources familiar with the issue said Turner's statement was related to Russia and operations in space, without providing further details on what was described as a highly-classified matter.

Turner's statement was released in the midst of intense debate in Congress over how the United States should be dealing with global threats from Russia and other rivals, with security hawks urging greater global involvement and some lawmakers most closely allied with former Republican President Donald Trump advocating for a more "America First" approach to world affairs.

The Biden administration has been ramping up its criticism of House Republicans for possibly blocking a $95-billion bill passed by the Senate that would supply aid to Ukraine, Israel and Taiwan. Supporters of the bill argue that a major reason for the United States to back the government in Kyiv is to push back against threats from Russia that extend beyond Ukraine.

House Speaker Mike Johnson, a staunch Trump ally who says he will not rush to allow a vote on the Senate bill, told reporters at the Capitol there was no need for public alarm. "Steady hands are at the wheel. We're working on it and there's no need for alarm," he said.

'NOT A CAUSE FOR PANIC'

Senators Mark Warner and Marco Rubio, the Democratic chairperson and Republican vice chairperson of the Senate Intelligence Committee, issued a joint statement saying their panel has the intelligence in question and has been "rigorously" tracking the issue.

"We continue to take this matter seriously and are discussing an appropriate response with the administration. In the meantime, we must be cautious about potentially disclosing sources and methods that may be key to preserving a range of options for U.S. action," the statement said.

A source familiar with the matter said Warner and Rubio had been briefed on the threat two weeks ago. The source said the issue was not unrelated to the security spending bill, but there is no direct tie between them.

Representative Jim Himes, the top Democrat on the House intelligence panel, said the issue in Turner's statement is significant, "but it is not a cause for panic."

"As to whether more can be declassified about this issue, that is a worthwhile discussion but it is not a discussion to be had in public," Himes said in a statement.

Jake Sullivan, President Joe Biden's national security adviser, declined to provide specifics. He said he had arranged a briefing for Thursday with congressional leaders and that he was surprised by Turner's decision to issue the statement.

"That's been on the books so I am a bit surprised that Congressman Turner came out publicly today, in advance of a meeting on the books, for me to go sit with him alongside our intelligence and defense professionals tomorrow," Sullivan told a briefing.

"I'm not in a position to say anything further today. Like I said, I look forward to the discussion with (Turner) and obviously from there we will determine how to proceed, but standing here at the podium today I can't share anything further," Sullivan said.

Sullivan made clear that he had initiated the meeting with the Gang of Eight scheduled for Thursday.

The Gang of Eight refers to the Republican and Democratic leaders of the House and Senate, and the top Republican and Democrat on the House and Senate intelligence committees.