Jan Hallenberg, a security policy expert and researcher at the Foreign Policy Institute, says the question is when and not if Iran will take revenge on the US after the deadly bomb attack on top general Qassem Soleimani last Friday.

- There is a saying in the Middle East a number of times now that is "Revenge is the right best served cold", which means that the enemy must sweat before striking, he says in SVT's Aktuellt.

Drone or missile attacks a possibility

Iran itself states that they are considering 13 different revenge scenarios.

- I think it's about different types of supposed attacks on US diplomats or military in the Middle East. A guess is some kind of drone or other missile attack, Hallenberg says.

Iranian leaders have spoken of a "historic nightmare" for the United States, something Jan Hallenberg thinks is an exaggeration:

- I have a very hard time imagining that they can launch such an attack that strikes so terribly hard against the United States. This is probably part of the exaggerated rhetoric that now exists on both sides.

He also believes that the answer will come from Iranian forces and not any militia backed by the country.

"The one who can possibly do something is Putin"

Representatives around the world have called for calm in the conflict, but Hallenberg believes that neither the EU nor the UN can cushion the tense atmosphere.

- Neither the US nor Iran consider them to be heavy enough.

- I personally think that the one who could possibly do something is the President of Russia, Putin, and his Foreign Minister Lavrov, because both parties would listen to them. It could be a possible way out. I have a hard time seeing any other mediator.