When Donald Trump was last in the White House, he pursued a policy of "maximum pressure" against the Islamic republic of Iran, including punishing sanctions.
Now that he is set to begin another term as US president in January, anxiety is mounting in Tehran that more of the same will follow.
During Trump's first term, the United States also killed a revered Islamic Revolutionary Guard Corps general in an air strike on Baghdad airport in Iraq.
Such history between the two long-time adversaries casts a dark shadow over the prospect of relations improving.