In the early hours of Sunday, in Azerbaijan, an explosion ripped through a packed nightclub located in Baku. There's no precise number of victims yet, but the incident was not likely to have come at an untimelier moment for Russian president Vladimir Putin.
Russia is forced to remove troops from “peacekeeping” duties in Georgia and Nagorno Karabakh, as they're needed to be deployed in Ukraine. Transferring “peacekeepers” allowed Azerbaijan to extend its influence over an area of ceasefire.
However, Azerbaijan has been developing close connections with Israel. Iran is a neighbor of Azerbaijan. Iran shares the border with Azerbaijan which is inhabited by Azerbaijanis and is not pleased that it has threatened Baku in regards to the relationship it has with Israel.
An investigation of the incident is ongoing.
There are plenty of negative feelings about the result of the Nagorno-Karabakh War. The two sides accuse each others of genocide. The attack could be an Armenian revenge for Azerbaijan's aggressiveness in the cease-fire zone. If that's the case, a fresh war is very likely, as Russia is in a state of anxiety and has proved to be an uninvolved paper tiger.
The Iranians tend to commit terror acts when they're angry over something. They have repeatedly threatened about being surrounded by Israelis, and these threats have been disregarded. Any country that is able to bomb the synagogue in Argentina for sh**s and grins can bomb a nightclub in which drinks are consumed, and both women and men, and perhaps Israelis mix. I'm not knowledgeable enough about relations between Iran and Azerbaijan to know what this might mean, or to even offer a rational speculation.
It is also possible that the incident was caused by an accident. The Director General of AzeriGas issued an announcement that it was an “propane gas cylinder” explosion. The statement is intended to suggest that it was an accidental explosion, however there is no indication as such. The phrase “propane gas cylinder” could be an explosive or part of something else or could just be untrue.
The key issue is the way in which the Azerbaijan government will deal with the blast. If they wish to strike back at Armenia, there is a possibility that an investigation will be initiated that gives the authorities the reason to do it. If they wish for to make this an incident, then they've created the conditions for their decision.