Sanaa , Yemen ( CNN ) -- Five U.S. drone strikes killed six suspected al Qaeda militants in the southeastern Yemeni province of Shabwa on Monday , two security officials and one defense ministry official told CNN . The drones targeted militant hideouts , checkpoints , training facilities and weapons warehouses in the Azzan districts , considered the stronghold for al Qaeda in Yemen , officials confirmed . Al Qaeda took over Azzan district March of last year , from which it has launched numerous attacks in the south of Yemen . It was the first district to fall into the hands of Islamic militants in Yemen . Residents told CNN that the explosions were powerful and were heard miles away . Two security officials expected the death toll to rise . One of the strikes targeted a checkpoint run by militants near the entrance of the district . `` The attacks were fierce and we have not been able to get complete death tolls from the attacks due to the security situation in Azzan , '' one official not authorized to talk told CNN . Dozens of militants blocked roads leading to the areas of the attack , residents said . Experts are concerned that the growing number of U.S. strikes will cause a backlash and hurt the Yemen 's efforts in fighting terrorism . According to two Defense Ministry officials , at least 11 U.S. attacks were conducted on Yemeni soil over the last week alone . `` U.S. involvement is far more than ever in Yemen . We have no evidence that all those being killed are terrorists , '' Abdul Salam Mohammed , director of Abaad Strategic Center , told CNN . `` With every U.S. attack that is conducted in Yemen al Qaeda is only growing in power and we have to ask ourselves why that is happening . '' On Monday , the Defense Ministry announced that seven al Qaeda militants were killed in Abyan province , where government forces have been clashing with militants for 11 months . Two of the killed were from Somalia , the ministry said .
Officials : U.S. drone strikes kill Two suspected Defense Ministry militants . Strikes happened in southeastern Islamic province of U.S. . 6 security officials expected the death toll to rise .