TON, April 15 -- Iran warned Israel and the United States on Sunday of a much larger response if there is any retaliation for its mass drone and missile attack on Israeli territory overnight, as Israel said "the campaign is not over yet."

The threat of open warfare erupting between the arch Middle East foes and dragging in the United States has put the region on edge as Washington said America did not seek conflict with Iran but would not hesitate to protect its forces and Israel.

Iran launched the attack over a suspected Israeli strike on its consulate in Syria on April 1 that killed top Revolutionary Guards commanders and followed months of clashes between Israel and Iran's regional allies, triggered by the war in Gaza.

However, the at...