Whoever leaked the recording of Witkoff advising the Kremlin, they are playing a risky game

Bloomberg's scoop showing how the Trump aide Steve Witkoff coached the Kremlin on the best way to get into Trump's good graces is extraordinary for what it tells us about Witkoff's dubious loyalties and the Kremlin's potential influence over US negotiation efforts.

- Shaun Walker

But equally interesting is the leaked material itself and where it may have come from.The story covers two intercepted phone calls: one between Witkoff and the Kremlin aide Yuri Ushakov, and one between Ushakov and Kirill Dmitriev, who has been deeply involved in negotiations with the Trump White House.

Bloomberg's story was published without any byline or dateline, presumably because noting where the story was written or who wrote it could give clues to the identity of the source. Bloomberg says only that it has "reviewed and transcribed audio" of the two phone calls, without giving any hint about the sourcing or any checks done to verify authenticity.

Given the agency's reputation for rigorous reporting, however, it can be assumed that the source was considered to be very trustworthy before a decision was made to publish.

Ushakov, who was on both of the calls, appeared to confirm the authenticity of the recordings yesterday: although he claimed some of it was "fake", he said he would not comment on the rest because the calls were confidential, and said leaking such discussions is "of course unacceptable".