Iran is planning a counterattack on Israel involving more powerful warheads and other weapons, the Wall Street Journal reported citing Iranian and Arab officials.

This comes a day after Iran’s Supreme Leader Ayatollah Ali Khamenei vowed a harsh retaliation of Israel’s October 26 attack.

The WSJ report also citied officials as saying that Iran isn’t planning to limit its response to missiles and drones. However, WSJ noted it remains to be seen whether the threats are real.