NAIROBI, Kenya (AP) - The al-Qaida mastermind behind the 1998 bombings of U.S. embassies in Kenya and Tanzania was killed this week at a security checkpoint in Mogadishu by Somali forces who didn't immediately realize he was the most wanted man in East Africa, officials said Saturday.

The death of Fazul Abdullah Mohammed - a man who topped the FBI's most wanted list for nearly 13 years - is the third major strike in six weeks against the worldwide terror group that was headed by Osama bin Laden until his death last month.

Mohammed had a $5 million bounty on his head for allegedly planning the Aug. 7, 1998, embassy bombings. The blasts killed 224 people in Nairobi, Kenya and Dar es Salaam, Tanzania. Most of the dead were Kenyans. Twelve Americans also died.

U.S. Secretary of State Hillary Rodham Clinton - who was on a visit to Tanzania on Saturday as Somali officials confirmed Mohammed's death - called the killing a "significant blow to al-Qaida, its extremist allies, and its operations in East Africa.

"It is a just end for a terrorist who brought so much death and pain to so many innocents in Nairobi and Dar es Salaam and elsewhere - Tanzanians, Kenyans, Somalis, and our own embassy personnel," Clinton said.

White House counterterrorism adviser John Brennan called Mohammed's death "another huge setback to al-Qaida and its extremist allies, and provides a measure of justice to so many who lost loved ones."

Mohammed was killed Tuesday but was carrying a South African passport, so Somali officials didn't immediately realize who he was. The body was even buried. Officials later exhumed it.

"We've compared the pictures of the body to his old pictures," said a spokesman for Somalia's minister of information, Abdifatah Abdinur. "They are the same. It is confirmed. He is the man and he is dead. The man who died is Fazul Abdullah."

Mohammed, a native of the Comoros Islands, was carrying sophisticated weapons, maps, other operational materials and tens of thousands of dollars when he was killed, Information Minister Abdulkareem Jama said. Family pictures and correspondence with other militants were also found, he said. The money, equipment and personal effects made officials take a second look at the death, he said.

"We congratulate our army for killing the head of al-Qaida operations in East Africa. They have shown their effectiveness," he said.

Earlier in the week, a Somali security officer had described to The Associated Press the deaths of two men in Mogadishu, one of whom is now believed to have been Mohammed.