U.S. and Iranian leaders have exchanged threats as their interim deal to end the war faces new challenges. President Donald Trump has threatened further missile attacks on Iran. This follows calls for his assassination at the funeral of Iranian Supreme Leader Ayatollah Ali Khamenei. Iran's new leader, Mojtaba Khamenei, vowed on Saturday to avenge his father's death. The U.S. has demanded Iran make a public statement saying the Strait of Hormuz is open and ships won’t be attacked. Iran's foreign minister is in Oman, located on the other side of the strait, for talks.