"While we can consider there being legitimacy in neutralising nuclear structures in Iran given the objectives we share... There is no legality in these strikes," Macron told reporters during a visit to Norway.

"We have consistently believed from the beginning that this can only be achieved through diplomatic and technical means," the French president said, speaking alongside Norwegian Prime Minister Jonas Gahr Store.

Store echoed the sentiment.

"International law has some clear principles on the use of force. It can be granted by the Security Council or it can be in pure self defence," he said, noting that this meant the strikes were "outside the realm of international law."

The French head of state also voiced his opposition to any intention of a regime change in Iran through military means.

"Every time we've made this choice, whatever the legitimacy of the initial approach ... we made a mistake," he said, adding that such actions had not led to increased stability in the past.

Macron added that Israeli strikes on Iran's Evin prison had nothing to do with Israel's "stated objectives" of destroying the nuclear programme and had endangered civilians.

Macron also warned of the economic impact on the global economy in the event of Iran closing the Strait of Hormuz.

"The consequences for the global economy, especially China and many others, would be massive, and I think it would prompt a lot of reactions," the president said.