Iran has reportedly shipped over 300,000 artillery shells and a million rounds of ammunition to Russia across the Caspian Sea in the past 6 months, according to a report by the Wall Street Journal.
Iran has mostly used cargo flights to ship weapons to Russia due to the inability of Ukraine and its allies to intervene.
Blocking the shipment of weapons in the Caspian sea would require the agreement of former Soviet republics in the area, including Turkmenistan and Azerbaijan.
The Wall Street Journal reported that the most recent weapons shipment known to have crossed the Caspian Sea to Russia left Iran in early March on a Russian cargo ship, carrying 1000 containers with 2000 artillery shells.
The United States has recently stepped up its ties in the region, with US CENTCOM commander Michael Kurilla visiting Turkmenistan and secretary of state Antony Blinken meeting with Turkmeni foreign minister Rasit Meredow in Washington on Monday.
Likewise, in December, the US fifth fleet – based out of Bahrain and active in the Persian Gulf, Red Sea and Arabian Sea – intercepted an Iranian ship smuggling weapons to Yemen.
British forces in the region has also intercepted several Iranian weapons smuggling attempts over the past few months.