Al-Qaeda bomb maker becomes America's worst nightmare

Running a clandestine bomb factory in remote area in Yemen, a nondescript Saudi has emerged as the most potent threat to the US, making three bids in past three years to spread mayhem in the world's most powerful nation.

His explosive devices are becoming increasingly sophisticated and hard-to-detect for Americans counter-intelligence forces who have now marked him as the nation's most wanted.

Ibrahim Hassan al-Asiri has emerged as CIA's worst nightmare since the slaying of terror chief Osama bin Laden and has now become a major focus of America's anti-terrorism efforts, CNN reported quoting US intelligence officials.

Asiri, 30, who hails from middle class Saudi family, US intelligence agency say is the top bombmaker for al-Qaeda's Yemeni branch whom they now call 'Evil Genius'.

US officials have said Asiri built the bomb in the attempts to bring down a commercial flight near Detroit and two cargo planes headed for the US. His latest bomb, part of yesterday's foiled plot, appear to be the most sophisticated and a modification of his underwear bomb, which caused ripples in American law enforcement agencies.

With the death of Osama bin Laden, Asiri is a key reason that US officials consider Yemen's al-Qaeda in the Arabian Peninsula (AQAP), to be one of the most significant threats to the American homeland.

"He is highly determined and fully committed to attack America," according to Arab security experts.

Over the past year, AQAP has taken advantage of Yemen's political turmoil and seized large swaths of territory in the south. Yemen's government and the Obama administration have responded with aerial assaults and drone strikes, targeting Asiri and other top operatives of AQAP.