Azerbaijani President Ilham Aliyev has complained to his Russian counterpart, Vladimir Putin, about Moscow’s arms sales to Armenia. The rare rebuke comes as the geopolitical alignments in the Caucasus are shifting somewhat following last month’s sharp outbreak of fighting.

Aliyev and Putin spoke by phone and the former brought up reports of large arms shipments from Russia to Armenia during and after the fighting, which the Azerbaijani president said “raises concerns and serious questions in the Azerbaijani society.”

“The main goal of the conversation was to clarify this question,” Aliyev’s press service said in an August 13 release.

Aliyev was referring to reports the week before in pro-government Azerbaijani media that several tons of weapons were shipped from Russia to Armenia between July 17 and August 4. (Aliyev told Putin it was 400 tons, though the most detailed report, in the news website day.az, said it was 280 tons.) The flights, using an IL76 military cargo plane, reportedly took a circuitous route from the southern Russian city of Rostov-on-Don to Armenia, avoiding the direct route – over Georgia – and instead circling around Kazakhstan, Turkmenistan, and Iran before entering Armenian airspace from the south.

Russian arms supplies to Armenia are not news: The two countries are treaty allies via the Collective Security Treaty Organization (CSTO) and Russia has long supplied Armenia with weapons at cost, a discount for CSTO members. But Azerbaijanis objected to the scale and timing of these shipments, suggesting that Russia was trying to provoke Armenia into attacking.

“These weapons were delivered to Armenia exactly on the eve of the attacks it carried out,” the website minval.az wrote. (In fact, the Armenia-Azerbaijan clashes started July 12, and the question of who started the fighting remains unanswered.) “A coincidence? It doesn’t seem so. In the Armenian armed forces they understand well that behind these kinds of weapon ‘injections’ there is always a political decision. And it’s not surprising, that these Russian military transport flights were perceived in Yerevan as an unambiguous ‘green light’ for a new provocation.”

Aliyev’s message to Putin was a slightly different one; he said that “the main goal of Armenia’s military attack was to draw third countries into the Armenian-Azerbaijani conflict,” though he didn’t specify which third countries he was talking about. (The use of the plural is conspicuous, however.)

The reports in the Azerbaijani media couldn’t be independently corroborated, but the information available in open sources do suggest that the plane identified did fly at the times reported, though their full itinerary and cargo remained unclear. Flightradar24 tracked one of the Russian flights mentioned in the Azerbaijani media reports, and found that it did cross from Iranian to Armenian airspace at the time reported.

Armenian officials and media have remained silent about the Azerbaijani reports.

Regardless of what was true about the arms shipments, what is clear is that the Azerbaijani government wants to use the reports as a lever against Russia. The report of Aliyev’s call was intriguingly timed, as a Turkish military delegation including Ankara’s defense minister was visiting Baku to observe joint military exercises.

While, in theory, Armenia is backed by Russia and Azerbaijan by Turkey, the real interests of the larger powers in the Caucasus conflict is often ambiguous and shifting.

Turkey’s response to the recent outbreak of fighting between Armenia and Azerbaijan has been noticeably stronger than in the past, with stronger expressions of support and from higher levels of the government. The ongoing military exercises are a yearly event, but their timing this year, and the relatively larger number of Turkish troops involved, makes them appear to be a show of force in support of Azerbaijan, and many Azerbaijanis have cheered them.

It’s still not clear to what extent Turkey would aid Azerbaijan in the case of a full-scale war, but the overt support from Ankara and the resulting public enthusiasm may have emboldened Baku to try to push Moscow toward a more assertive role in resolving the conflict.

Meanwhile, Russia has taken a relatively passive role in the fighting. The CSTO, where Russia effectively calls the shots, issued a statement during the fighting that was, from Yerevan’s perspective, disappointingly even-handed. Since then, Russia has not been particularly vocal, in contrast to Turkey’s regular shows of support.

Aliyev’s call has been accompanied by other assertive statements. “We are glad to share experiences with this strong army,” Azerbaijan’s Defense Minister Zakir Hasanov told journalists on August 13, referring to the exercises with Turkey. “The Turkish armed forces have demonstrated their power to the world in Syria, Iraq, and Libya. With the support of the Turkish military Azerbaijan will fulfill its sacred duty.” It is worth noting that in Syria and Libya, the Turkish forces have taken the opposite side from their Russian counterparts.

The Kremlin’s readout of Putin’s call with Aliyev did not mention any of the arms shipment controversies. It did note, however, that Aliyev had congratulated Putin for Russia’s claimed discovery of a COVID-19 vaccine.

With reporting by Ani Mejlumyan.