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The U.S. has hit Yemen with more than 30 airstrikes in less than 48 hours, and the al Qaeda targets killed include an expert bombmaker, according to two U.S. defense officials.

The death of Mossad al-Adani, al Qaeda's emir of Abyan governorate and an explosives expert, is a "blow to al Qaeda in the Arabian Peninsula," according to the officials. Also killed in that same strike was a former Guantanamo detainee,Yasir al-Silmi. He was at Guantanamo from 2002 to 2009

The U.S. conducted eight strikes overnight, targeting the same areas that were hit on Thursday morning: Abyan, al Bayda and Shabwah, all in Southern Yemen.

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Pentagon spokesman Capt. Jeff Davis said the targets for all of this week's strikes have been developed over the past several months, and that AQAP has "more American blood on its hands" than ISIS and other terror groups.

A defense official said the total number of AQAP fighters in Yemen is in the "low thousands."

Why has the pace of attacks picked up if the targets already existed?

In late January, President Trump authorized Defense Secretary Jim Mattis to carry out a mission to target AQAP in Yemen. Mattis then delegated that authority to the commander of U.S. Central Command, Gen. Joseph Votel. Now Gen. Votel can approve strike packages in Yemen himself, rather than running targets by Washington.

A U.S. military official said that the overall objective and mission in Yemen did not change since President Trump came to office — it is still to eliminate AQAP’s safe haven in Yemen and to eradicate the terror group. But, the official did acknowledge that the tactics have become more aggressive under President Trump and that giving Gen. Votel authority to approve strikes and targets himself makes the mission more efficient.

"Under President Obama we were focused on taking out the leadership and we didn’t put boots on the ground," said the official. "Now we are focused on going after the leadership and the entire network."

On Friday, a defense official also said that the January 29 raid by Navy SEALs on an alleged al Qaeda compound in which one SEAL died generated "large volumes of information" that is helpful in understanding the AQAP network — "good information" that is "potentially actionable."

"It's the largest collection of material we have gotten in some time," said another official. But he also said, "A lot of what we found we already knew."