An al Qaeda expert on chemical and biological weapons is reported to have been killed in a missile strike.
The ABC reports it happened in the tribal south Waziristan area of Pakistan on Monday.
Egyptian Midhat Mursi al-Sayid Umar, also known as Abu Khabab al-Masri, had a $US5 million bounty on his head.
Officials earlier said three Arab fighters and three Pakistani boys were killed when missiles reportedly fired from a United States drone hit a house attached to a mosque in the south Waziristan tribal district.
Pakistan's military said it was still seeking confirmation. The US Central Intelligence Agency is known to operate drones in the region.
Claims that Umar was killed in another air strike in the Bajaur tribal region in January 2006 turned out to be false.