Hamza was designated a global terrorist by the US in 2017 after he called for acts of terrorism in Western capitals and threatened to take revenge against the United States for killing his father.
Hamza, believed to be about 30 years old, was at his father's side in Afghanistan before the Sept. 11, 2001, attacks on the United States.
Germany deported Sami Aidoudi last month but a German court on Wednesday demanded his return.
Decades-old animosity between Sunni Muslim kingdom of Saudi Arabia and revolutionary Shi'ite Iran has deepened in recent years.
Small groups of students chanting "Death to America" and "Death to Trump" burnt American flags and torched photos of Trump after Friday prayers in capital Islamabad and the eastern city of Lahore.
Trump is hardly alone in noting Iranian links to al-Qaida.
When the dust settled and the smoke cleared, 2,997 people were dead, another 6,000 were injured and the course of history was changed forever.
The events of the day that prompted the war on terror, which continues on today.
How an apathetic American public is letting terrorism thrive again.