The United States has said that defense cooperation between Russia and Iran is strengthening, and that Moscow has acquired hundreds of drones from Tehran that have also been used to attack Ukraine.

In classified documents released by Reuters, the White House said the drones were manufactured in Iran, transported via the Caspian Sea and used by Russian forces against Ukraine.

“Over the past few weeks, Russia has used Iranian drones to attack Kiev and terrorize the Ukrainian people, and the military partnership between Russia and Iran is deepening,” White House spokesman John Kirby said.

“We are also concerned that Russia is working with Iran so that Iranian drones can be manufactured in Russia,” he said.

According to spokesman John Kirby, the United States had information that Russia was acquiring materials from Iran to build a drone manufacturing plant that would be fully operational early next year.

He said that they are releasing photos of the location of the plant which will be established in Russia’s Alaboga Special Economic Zone.

Earlier, the US has also imposed sanctions on Iranian officials for supplying drones to Russia.

Iran has also admitted to sending drones to Russia, but Iran says that these drones were exported before the attack on Ukraine.

On the other hand, Russia has also been rejecting the allegations that Iranian drones have been used to attack Ukraine.

White House spokesman John Kirby said that in bilateral relations between Iran and Russia, Tehran has received extraordinary defense support from Moscow in missile, electronics and air defense.

According to John Kirby, moving the drones is a violation of UN rules and the US will hold both countries accountable.

Britain, France, Germany, the United States and Ukraine have also said that the supply of Iranian-made drones to Russia is a violation of a 2015 Security Council resolution.