Psaki also confirmed the bomber's nom de guerre, Abu Huraira al-Amriki ("The American"), but did not disclose other details despite prodding by reporters.
According to an online statement by al-Nusra Front, the al Qaeda affiliate to which Abu Huraira reportedly belonged, he drove a heavy truck packed with 16 tons of explosives into a stronghold of government troops in northern Syria. He was accompanied by three other al-Nusra bombers, two of whom successfully blew themselves up. The third retreated to safety before his truck detonated.
Rebel fighters lauded The American, saying that the Islamic convert went willingly to kill others and himself. CNN reports Abu Huraira grew up and attended school in south Florida, while pictures reportedly depicting the red-bearded jihadi circulate the internet.
High-ranking U.S. officials have expressed concern about growing numbers of Americans being radicalized abroad. They fear citizen radicals could re-enter the United States undetected to carry out terror attacks.