The Russian ministry of defense posted this video that it said shows launches of Kalibr-NK cruise missiles from ships deployed in the Caspian sea. The strike is said to have reached targets in Syria, which means that the range of the missiles is definitely more than 500 km. Indeed, the minister of defense told the president that the actual range was "more than 1500 km."
If the cruise missiles did indeed reach their targets (and there is no particular reason to doubt that), this is a clear demonstration of a cruise missile with a range of more than 500 km. Had Kalibr-NK been a ground-launched cruise missile, it would be prohibited by the INF Treaty. However, the missile demonstrated in action today is a SLCM that the treaty does not limit in any way. Having said that, if this missile was ever test-launched from a mobile land-based launcher, it would be considered GLCM for the purposes of the INF Treaty and this test would be a treaty violation.
This was very much my theory of the Russia's treaty violation - Russia has tested a long-range SLCM (which it is allowed to have) from a wrong kind of launcher, landing itself in technical violation of the INF Treaty. At some point I started having doubts about this theory, since the United States insisted that "this violation is not a technicality or a mistake as some have suggested." Since I'm very much the only one who has suggested that, I guess Rose Gottemoeller had my hypothesis in mind when she said that. However, the Kalibr-NK launches appear to support my take on the issue. It is, of course, entirely possible that it is not a technicality in the sense that Russia deliberately tested Kalibr-NK from a land launcher, knowing full well that it is against the INF Treaty. Even though I have my doubts, I cannot completely rule out the possibility.
On thing to keep in mind in this debate is that a cruise missile is a cruise missile and the difference between an SLCM and a GLCM is very much non-existent. From the legal point of view, what matters is what kind of launcher the missile was tested from. But even if a missile was tested from a non-compliant launcher, this would not be a militarily significant violation if Russia does not produce these launchers in large numbers (which would indicate preparation for mass deployment). So far, we haven't seen the launchers, so my guess is that the violation is still closer to a technicality than to a deliberate breakout from the treaty.
Now to the missile. There is still a bit of uncertainty there, but it seems that we are dealing with some version of the 3M14 missile of the Kalibr family. However, unlike publicly known missiles of this family, like 3M14E Kalibr-M, Kalibr-NK appears to be a longer missile - about 8 m vs. 6.2 m of the short-range Kalibr-M. This puts Kalibr-NK closer to the SS-N-21 SLCM and its ground-launched version, RK-55 Relief/SSC-X-4. I was told heard about a 8-meter missile at the early stages of this story. This does not seem to fit the 9M729/Iskander follow-on theory of the INF violation. Quite literally, a 8 meter-long missile will not fit into the about 7-meter long weapon bay of the Iskander launcher.
Whoever is the INF culprit, the Pentagon apparently has a name for it - SSC-X-8. According to Bill Gertz sources, Russia tested this missile again on September 2, 2015. Kalibr-NK is probably what his earlier article refer to as SSN-30A.
UPDATE 10/11/15: The U.S. administration insists that my theory is wrong and that the INF culprit is not an SLCM:
Learned from an administration official today that Russia's INF-noncompliant missile is not a SLCM tested from a land based launcher— Kingston Reif (@KingstonAReif) October 10, 2015
My guess would be that this does not necessarily mean that the missile itself is different - after all, there are only so many types of missiles Russia can realistically have under development. But this suggests that there is a dedicated launcher developed to carry the missile. But the administration pronouncements remain rather cryptic at this point. I think everybody would win if the United States releases more details about the missile.