Foreign ministers at a summit of eight European and Middle Eastern countries have urged the US and Israel not to renews their attacks on Iran, warning a fresh outbreak of fighting would spread conflict and push oil prices even higher.

The development of a new multinational “anti-war bloc” represents a challenge to the increasingly open plans by the US and Israel to relaunch strikes on Iran while talks on Tehran’s nuclear programme remain deadlocked.

The Turkish foreign minister, Hakan Fidan, joint convener of the summit in Istanbul, said: “Military intervention in Iran is not any kind of solution. We agreed that a new military attack would spread the war and the conflict in the region.…