The U.S. has designated as a terrorist an al-Qaida bomb maker suspected of involvement in trying to assassinate a Saudi prince and bring down a Detroit-bound airliner in 2009.
The State Department banned Americans from doing business with Ibrahim Hassan al-Asiri.
A statement called al-Asiri the primary bomb maker for al-Qaida in the Arabian Peninsula.
In October, Al-Asiri's brother wounded Prince Muhammed bin Nayef, deputy Saudi interior minister, after setting off explosives hidden in a body cavity.
The U.S. said "the brutality, novelty and sophistication of the plot" dramatizes al-Asiri's threat.
Al-Asiri is suspected of packing explosives into the underwear of a Nigerian who tried to blow up the Detroit-bound airliner on Christmas 2009, and making the bombs found on U.S. cargo planes last year.
Al-Asiri operates from Yemen.