Iran's president promised to avenge the assassination of Qassem Soleimani. Using strong words, the president said: "The Americans do not realise what grave error they have committed. Revenge for Soleimani's blood will be secured, and the filthy hands of America will be cut off forever from this region." Iran's religious leader was similarly defiant. He said: "Severe retaliation awaits murderers with blood on their hands." Mr Soleimani's death will increase tensions.

Qassem Soleimani, 62, was the second most powerful person in Iran. He was the top military leader and was behind Iran's spreading regional influence. Some media call him the "rock star general". The U.S. president ordered the assassination after the killing of an American in the U.S. embassy in Baghdad. He said the assassination was to stop war in the region. He called Soleimani a terrorist who was responsible for thousands of deaths. "World War III" is now a top hashtag on social media.