Lt Gen Alexus Grynkewich said during a press conference at the US embassy in Abu Dhabi that the two countries' expanding military ties were focused on Iranian provision of drones to Russia, weapons which Tehran has also supplied to proxy militias across the region.
Moscow has received hundreds of Iranian Shahed-136 one-way attack drones – sometimes called kamikaze drones and which Russia calls Geran-2 – for use in its war in Ukraine. Iran has also sent Russia its Mohajer drones for use in the conflict.
Similar small attack drones, such as the Qasef, have been provided to Houthi militias in Yemen.
Both Kyiv and Moscow have been losing tens of thousands of drones per month in the conflict, which has seen the unprecedented use of unmanned aircraft for reconnaissance and attacking enemy positions.
“Who would have ever thought that the Russian Federation would need to go to Iran for military capabilities? And yet we’re there,” Lt Gen Grynkewich said.
“That means that Russia actually owes Iran something. I’m concerned about the level of collaboration that might happen.”
His remarks follow a visit on Wednesday by Russian Defence Minister Sergey Shoigu to Tehran, where he met military officials including National Security Council chief Ali Akbar Ahmadian and viewed some of Iran’s latest military hardware.
“We are aiming at an entire range of planned activities, despite opposition from the United States and its Western allies,” the Interfax news agency cited Mr Shoigu as saying.
Iran's Tasnim news agency reported that Russia's Defence Minister also visited the Islamic Revolutionary Guard Corps' Aerospace Force, where he met the branch's head, Amirali Hajizadeh, during a viewing of Iranian drones, missile and air defence systems.
Mr Shoigu said relations between Russia and Iran are strengthening despite opposition from much of the western world.
“Sanctions pressure on Russia and Iran shows its futility, while Russian-Iranian interaction is reaching a new level,” he said.
Speaking of the ongoing Washington-led mission against ISIS in Iraq and Syria, Lt Gen Grynkewich said Russia’s presence in the region was no deterrent to the ongoing US deployment, despite what he characterised as attempts by Moscow to harass US drones.
“Part of our approach here in the Middle East was to be able to surge forces into the region when the threat warrants. It is an enduring commitment here to the region. We are not going anywhere,” he said.