The Group of Seven (G7) industrialized powers told Iran on Friday not to transfer ballistic missiles to Russia to use in its conflict with Ukraine, warning that they would take action against Tehran if it did so.

"Were Iran to proceed with providing ballistic missiles or related technology to Russia, we are prepared to respond swiftly and in a coordinated manner including with new and significant measures against Iran," the G7 leaders said in a statement.

Iran has provided Russia with a large number of powerful surface-to-surface ballistic missiles, sources told Reuters last month, deepening the military cooperation between the two countries, which are both under U.S. sanctions.

The G7 statement did not say whether it believed Russia had already received Iranian missiles, suggesting that Tehran was still reviewing the possibility.

"We are extremely concerned about reports that Iran is considering transferring ballistic missiles and related technology," the statement said.

"We call on Iran not to do so, as it would add to regional destabilization and represent a substantive material escalation in its support for Russia's war in Ukraine," the G7 said, adding that Tehran had already provided Russia with drones that it had used against civilians.

The G7 group of major Western democracies is currently chaired by Italy and also includes the United States, Japan, Germany, Britain, France and Canada.

The statement came as the European Union is also considering measures against Iran for arming Russia, Reuters reported this week.