The United States on Thursday offered a $1 million reward for information on a son of late al-Qaida leader Osama bin Laden, seeing him as an emerging leader of the terrorist network.

The State Department described Hamza bin Laden as a "key leader" within al-Qaida who is growing in prominence within the U.S.-designated terror group.

Later on Friday, Saudi news outlets reported that the kingdom has stripped him of his citizenship.

The junior bin Laden has released audio and video messages on the internet calling for attacks against the West and has threatened revenge for his father's 2011 killing by U.S. forces, the department said in a statement.

The location of Hamza bin Laden has been the subject of speculation for years with reports of him in Pakistan, Afghanistan or under house arrest in Iran.

He was added to the U.S. counter-terrorism blacklist in 2017 for being an active propagandist of al-Qaida in the Arabian Peninsula (AQAP). He is said to have married the daughter of Mohammed Atta, the lead hijacker in the Sept. 11 terror attacks on the U.S.

Osama bin Laden was killed at his Pakistani hideout by U.S. commandos in 2011 in a major blow to the al-Qaida terrorist group, which carried out the Sept. 11 attacks.

Bin Laden claimed responsibility for the Sept. 11, 2001, attacks on New York's Twin Towers, as well as the attack that day on the Pentagon.

Those attacks were carried out using three passenger planes hijacked by al-Qaida operatives. A fourth plane, bound for either the White House or the Capitol, crashed in a field in Pennsylvania after passengers attempted to retake it from the hijackers.

Nearly 3,000 people were killed that day, including citizens of roughly 77 countries.