(CNN) A son of Osama bin Laden is emerging as a leader in al Qaeda, the US State Department says, and it's willing to pay up to $1 million for information on his whereabouts.

Hamza bin Laden, whose father was killed by US Navy SEALs in Pakistan in 2011, is taking the reins of the terror group, the State Department said late Thursday.

The State Department wants information on Hamza bin Laden.

"Hamza bin Laden ... is emerging as a leader" in the al Qaeda franchise, the department said in a statement. "He has released audio and video messages on the Internet, calling on his followers to launch attacks against the United States and its Western allies, and he has threatened attacks against the United States in revenge for the May 2011 killing of his father by US military forces."

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The State Department said items seized from the elder bin Laden's hiding place in Pakistan at the time of his death indicated he was grooming Hamza bin Laden to replace him as al Qaeda's leader.

The younger bin Laden is married to the daughter of Mohammed Atta, the lead hijacker in the September 2001 attacks on the World Trade Center, the State Department said.

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