It "appears likely" that the war on terrorism has succeeded in killing another key member of the al Qaeda network, intelligence sources tell ABC News.
And sources say the weapon was a U.S. anti-terror weapon that is a high-tech flying robot -- a CIA Predator.
In Kuwait on an official visit, Pakistani President Pervez Musharraf said he had no doubt that one of the men killed was a top al Qaeda operative, Abu Hamza Rabia, saying Rabia's death was "200 percent confirmed."
Rabia was indeed the target of a missile attack near Pakistan's rugged northwestern border with Afghanistan, an area called North Waziristan, U.S. intelligence sources tell ABC News.
North Waziristan is where the CIA thinks al Qaeda leader Osama bin Laden might be hiding. Rabia was an al Qaeda terror planner, and one of bin Laden's top deputies.
"He would have been the one trying to mount operations both inside Afghanistan, Pakistan and overseas," said Richard Clarke, a former U.S. counterterrorism official and an ABC News consultant.
Intelligence sources say the attack was carried out by a CIA Predator -- a small, unmanned aircraft linked by satellite to a command center that can be halfway around the world.
"This is basically a model airplane on steroids," Clarke said. "It has a small, very quiet propeller engine driven by aviation fuel. It's basically best thought of as a robot."
A pilot controls the Predator with a joystick and sees video images from the aircraft in real time -- just like a video game.
The Predator can be armed with laser-guided, anti-tank missiles called "hellfires." Commanders in the United States can launch an immediate attack if the Predator's controllers spot a target.
"This is an extraordinary asset because it can stay up for a full day, quietly circling, looking at a facility over and over again," Clarke said. "The Predator is perhaps the first robot ever to kill a human being."
Predators have been used against al Qaeda operatives before. In November 2002, one fired missiles on a car in Yemen, killing all six men inside. But Predators can be, and have been, shot down. Yet the pilot is always safe and sound, thousands of miles away.