The head of Roscosmos, Igor Komarov, has formally stated that the agency has no telemetry information that anything went wrong with the Breeze-M (Briz-M) upper stage. This was after Brazilian observatory reports noting that fiery debris appeared to indicate that an explosion had taken place on the stage shortly after the release of the ESA ExoMars mission. http://spacenews.com/roscosmos-gives-detailed-rebuttal-to-reports-of-proton-upper-stage-anomaly-after-exomars-separation/
For those wanting more tangible evidence that the Breeze-M had not exploded was that US Strategic Command have recent tracks of the upper stage’s toroidal tank and main engine sections. These appear to be intact and separated as planned.
