Iran and Azerbaijan have had a volatile diplomatic relationship ever since Azerbaijan gained its independence 20 years ago. But even against the backdrop of their bumpy history, the deterioration in relations over the past few months has been swift. Azerbaijan’s recent moves to strengthen its alliance with Israel have certainly exacerbated tensions with Iran, but they are not the only cause of conflict. In addition to the two sides’ history of mutual suspicion, violent disagreement over sovereignty and each other’s choice of regional diplomatic partners are also prominent causes of strife.
A central source of long-term tension between the two neighbors is the legal status of Iran’s ethnic Azeris, who comprise 16 percent of Iran’s population. Although some ethnic Azeris in Iran have dual citizenship, Azerbaijan sometimes claims sovereignty over all ethnic Azeris and has at times commented on legal issues affecting Iran’s Azeri minority population. Recently published school textbooks in Azerbaijan even relabeled Iran’s northern border province “Southern Azerbaijan.” When Azerbaijan's president, Ilham Aliyev, gave a domestically uncontroversial 2011 speech describing himself as leader of all the world’s Azeris, the Iranian government took offense. The chairman of the Iranian Parliament’s National Security and Foreign Policy Committee, Alaeddin Borujerdi, dismissed the declaration as reflecting the “innate sense of inferiority” that Azeris feel toward Iran. The Iranian press portrayed Aliyev’s comments as irresponsible, accusing him of soliciting dual loyalties among Iran’s Azeri population.
Since its 1979 revolution, Iran has sporadically but unofficially suppressed Azeri-language publications and cultural organizations. More recently, Iranian officials have accused some Azeris who routinely travel between Azerbaijan and Iran of being spies for the Azeri government. As justification, officials point to Baku’s increased cooperation with Israel, Aliyev’s claim of sovereignty over Iranian Azeris and alleged recruiting by Western intelligence agencies in Azerbaijan, which Tehran says is widespread. Iran recently detained several Iranian Azeris suspected of cooperating with Israel in the killings of several nuclear scientists, part of what Iranian officials believe to be a wide-ranging espionage campaign.