America has been trying its level best to create a rift between Russian and China. If it cannot achieve that objective, then the next best thing is a war between states backed by Russia and states backed by China. If that is not possible, then the next best thing is a war between a state backed by China's allies and a state backed by Russia. That would be a war between Azerbaijan and Armenia, or a war between Azerbaijan and Iran. Now is not the time to let America lure us into a useless war.
If the exercises near Caspian Sea are an issue, then Iran's reservations could have been satisfied by inviting Iran to join. And, strange as it may sound, just like under the SCO banner Pakistan and India joined the same military exercise in Russia, it would be a foreign policy genius if a military exercise could invite Pakistan, Iran, Turkey, Armenia, AND Azerbaijan. This is how you build trust, this is how you show leadership and foresight, and this is how you defeat your enemies.