Iran has acknowledged sending drones to Russia, for the first time, but says it was before the war in Ukraine.
Iranian drones have been seen on the battlefield in Ukraine and used to target power stations and civilian infrastructure.
Iranian Foreign Minister Hossein Amirabdollahian confirmed a "small number" of drones had been supplied to Russia.
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Speaking to reporters in Tehran, he said: "We gave a limited number of drones to Russia months before the Ukraine war."
He also claimed that Iran was oblivious to the use of its drones in Ukraine, adding that "if [Ukraine] has any documents in their possession that Russia used Iranian drones in Ukraine, they should provide them to us."
He added: "If it is proven to us that Russia used Iranian drones in the war against Ukraine, we will not be indifferent to this issue."
Previously, Iranian officials had denied arming Russia in its war on Ukraine.
Just last week, Iran's ambassador to the UN, Amir Saeid Iravani, called the allegations "totally unfounded" and reiterated Iran's position of neutrality in the war.