The car bomb exploded outside the prime minister's offices in Sanaa, German outlet Deutsche Welle reported. At least 12 other people, including seven bodyguards, were killed in the blast.
A Yemeni security official confirmed to AFP that the defense minister was the target, and that "the explosion was the result of a bomb-laden car."
No one has yet claimed responsibility for the attack, but the Christian Science Monitor pointed out that it "bore the hallmarks of al-Qaeda."
On Tuesday, Ayman al-Zawahiri, Osama Bin Laden's replacement as Al-Qaeda's head, confirmed the "martyrdom of the lion of Libya, Sheikh Hassan Mohammed Qaed," using the birth name of Abu Yahya al-Libi, the head of Al-Qaeda's Yemen's operations, Reuters reported.