UPDATE 2:
NBC News has learned exclusively from sources that Senate Intelligence Committee Chairman Richard Burr and Vice Chairman Mark Warner met with Speaker Paul Ryan on February 15. The New York Times had previously reported the meeting occurred last month.
— Marianna Sotomayor (@MariannaNBCNews) March 1, 2018
UPDATE: CNN's Senior Congressional Correspondent tweets:
Burr flatly denies report that his panel has concluded that Nunes/House Rs behind leak of Warner texts. Says: “No,” when asked if SSCI concluded that. He also denied they raised concerns about Nunes to Ryan. “We met with Speaker Ryan to update on our investigation. That was it."
— Manu Raju (@mkraju) March 1, 2018
The New York Times reports that Senate Intelligence Committee leadership – Chairman Richard Burr (R-NC) and Vice Chairman Mark Warner (D-VA) – has discovered that House Intelligence Committee Chairman Devin Nunes' (R-CA) staff is responsible for leaking Senator Warner's private text correspondence with a Russian-connected lawyer to Fox News.
The messages between Mr. Warner and Adam Waldman, a Washington lawyer, show that the senator tried for weeks to arrange a meeting with the former spy, Christopher Steele. The Senate committee has had difficulty making contact with Mr. Steele, whom it views as a key witness. And Mr. Waldman, who knew Mr. Steele, presented himself as a willing partner.
(...)
Copies of the messages were originally submitted by Mr. Waldman to the Senate committee. In January, one of Mr. Nunes’s staff members requested that copies be shared with the House committee as well, according to a person familiar with the request who was not authorized to talk about it publicly. Days later, the messages were published by Fox News, the person said. Fox’s report said that it had obtained the documents from a Republican source it did not name.
The documents published by Fox News appear to back up the senators’ accusation. Though they were marked “CONFIDENTIAL: Produced to USSSCI on a Confidential Basis,” suggesting that they had come from the Senate panel, known as the United States Senate Select Committee on Intelligence, the person familiar with the congressional requests said that the stamp was misleading and that other markings gave away their actual origin.
Specifically, the copy of the messages shared with the Senate was paginated, and the one submitted to the House — while preserving the reference to the Senate committee — was unpaginated.
Senators Burr and Warner approached House Speaker Paul Ryan to discuss the breach in particular and Rep. Nunes' behavior in general.
[They] were so perturbed by the leak that they demanded a rare meeting with Speaker Paul D. Ryan last month to inform him of their findings. They used the meeting with Mr. Ryan to raise broader concerns about the direction of the House Intelligence Committee under its chairman, Representative Devin Nunes of California, the officials said.
(...)
In a statement, a spokesman for Mr. Nunes, Jack Langer, did not dispute that the committee had leaked the messages, but called the premise of this article “absurd.”
Senate Intelligence Leaders Say House G.O.P. Leaked a Senator’s Texts (NYT)