Von der Leyen said that she agreed with Netanyahu in a telephone call that "Iran should not have a nuclear weapon, without any question."

"Of course I think a negotiated solution is, in the long term, the best solution," she said at a press briefing at a Group of Seven summit in Kananaskis, Canada.

Israel launched a surprise and massive military attack on Friday on Iran, which has responded with a barrage of missiles and drones on Israel.

Von der Leyen -- who has been critical of Israel over its offensive in Gaza -- placed the blame for the new conflict on Iran, pointing to the UN nuclear watchdog's finding earlier in the week that it was not in compliance with its obligations.

"In this context, Israel has the right to defend itself. Iran is the principal source of regional instability," von der Leyen said.

She said that the G7 summit should discuss the Iran crisis alongside Ukraine, which has been hit by drones sold to Russia by Tehran's cleric-run state.

"The same type of Iranian-designed and -made drones and ballistic missiles are indiscriminately hitting cities in Ukraine and in Israel. As such, these threats need to be addressed together," she said.

European Council chief Antonio Costa, speaking alongside her, said it was "time to give space for diplomacy" and to "give opportunity to decrease the escalation between Israel and Iran."

Iran in response to the UN watchdog said it would ramp up output of enriched uranium, although not at levels to make nuclear weapons.

Israel is widely known to have nuclear weapons but does not publicly acknowledge them.