It is no longer a secret that Iran is supplying Russia with attack drones destined for use against Ukraine, but it now appears that the Islamic Republic is also sending rockets, mortar shells, and bullets by the millions to Moscow. 

More precisely, they’re being sent to Astrakhan, the large Russian city at the mouth of the Volga River on the northern perimeter of the Caspian Sea. Just south of the  opposite end of that vast inland sea lies the Iranian capital, Tehran. 

According to an investigation conducted by Britain’s Sky News, Iran was recently able to secretly supply Russia with an extensive batch of munitions that is said to have  included 100 million bullets and 300,000 artillery shells and was dispatched surreptitiously across the Caspian Sea. In January two commercial ships bound for Astrakhan, the Musa Jamil and Begay, which carried 200 containers of munitions, allegedly sailed forth from Iranian ports.

The vessels’ early winter voyages to Astrakhan from Iran were verified by Marine Traffic’s electronic vessel tracking system. Their trajectory was also reportedly visible in satellite photos.

The report underscores the increasingly cozy military ties between the two countries and would also appear to lend credence to the charge that the Russian strongman, Vladimir Putin, is using Iran as a rear base for his ongoing invasion of Ukraine. 

It was not possible to independently confirm the illicit cargo, but according to Sky’s source it also included ammunition for rocket launchers, mortars, and machine guns, as well as 10,000 helmets and flak jackets. Moscow is said to have paid for the ammunition in cash. Neither Russian authorities nor the shipowner responded to Sky News’s requests for comment, but Russia has denied purchasing Iranian military wares in the past. 

After more than a year of an intensely fought war, the Kremlin’s weapons stocks are undeniably diminished, though exactly to what extent is difficult to ascertain. Mr. Putin’s mercenary man in the Donbas, Yevgeny Prigozhin, recently complained about a lack of ammo as his ragtag Wagner forces attempt to close in on the Ukrainian city of Bakhmut and other parts of the fiercely contested region, leaving little doubt as to the utility for Russia of a fresh supply of weapons of convenient Iranian provenance. 

On top of the hundreds of Shahed “suicide drones” that Tehran has supplied to Moscow’s war machine, the prospect of Iranian-made bullets flying across the frontlines in eastern Ukraine could in the short term complicate military planning at Kyiv, because after months of relentless counterattacks Ukraine’s arsenals too are understood to be less robust. There will also ostensibly now be more pressure on Washington to hold the hardline Tehran regime to account as this and possibly other reports of Iranian connivance come to light. 

In the meantime the national intelligence director, Avril Haines, told the Senate Intelligence Committee on Wednesday that in 2023 Russia might have to shift to a more defensive posture in the territories it seeks to control in Ukraine on account of high casualty rates, a lack of troops, and insufficient ammunition. 

“If Russia does not initiate a mandatory mobilization and identify substantial third-party ammunition supplies, it will be increasingly challenging for them to sustain the current level of offensive operations in the coming months,” Ms. Haines said. 

Weapons traversing the Caspian Sea could pose a real predicament for Ukraine and its Western allies. Unlike the Black Sea — or, for that matter, the Persian Gulf — the waters of the inland Caspian Sea are not plied by a wide range of international vessels and in fact are home to the Russian Caspian flotilla. That would make intercepting illicit weapons transfers by Iran virtually impossible. Of course, that does not rule out military overflights or drone surveillance of the sea by relevant Western powers. 

There is also a growing awareness in Israel of the extent to which the most malign actor in the region, e.g., Iran, is brazenly giving a lift to Russian belligerence. Iran’s state-owned airline has previously been thought to have been used to smuggle long-range armed drones into Russia. 

How and whether the Biden administration is equipped to respond to a metastasizing Iranian threat in an increasingly complex tangle of war remains to be seen.

There was no immediate comment from Iran about the Sky News report.