German Foreign Minister Annalena Baerbock said Israel must comply with international law when considering its response to Iran's massive aerial attack.
"The right to self-defence means defence against an attack. Retaliation is not a category in international law," Baerbock said in response to a journalist's question about whether Israel had the right to retaliate.
Iran's launch of 300 drones and missiles toward Israel on Saturday had brought the region to the brink of all-out war, Baerbock said.
"At the same time, however, this escalation has also shown that the region stands by Israel when it comes to curbing dangerous Iranian behaviour. Iran is isolated," she said at a meeting in Paris on Monday.
"Israel has won in a defensive manner, thanks to its strong air defence and thanks to the courageous intervention of the US, Britain and Arab states," Baerbock continued. "This defensive victory must now be secured diplomatically. Our priority must be to prevent a conflagration in the region."
Baerbock said she had spoken with Iranian Foreign Minister Hussein Amirabdollahian to warn him against any further escalation from Tehran.
Israel has said it reserves the right to respond militarily following Iran's attack, which was almost entirely repelled by air defences.
Iran said the attack was retaliation for for the killing of high-ranking military officers in Syria.