Iran, which denies seeking to develop a nuclear weapon, has insisted it will not give up domestic uranium enrichment despite the bombings of three nuclear sites. Trump told reporters that Iran has been sending out "nasty signals" and any effort to restart its nuclear program will be immediately quashed.

Iranian and European delegations will gather in Istanbul, Turkey, on Friday for fresh talks on Tehran's nuclear program.

Russia said on Wednesday it was concerned about the threat of new strikes on Iran's nuclear facilities, and that a deal on Tehran's nuclear programme could be reached through dialogue.