` ` There is an increased threat stream , '' says a senior American official . The two military brigades currently in southern Shabwa province , which includes Azzan , `` ca n't try to follow those militants on the move and are preoccupied with securing the ( liquefied natural gas ) facilities , '' the official said . At least four suspected al Qaeda fighters were killed in a Yemen - U.S. joint operation . Yemeni authorities are on high alert , expecting ` ` imminent retaliatory attacks , '' an official says .
` ` There is an increased threat stream , '' says a senior American official . At least four suspected al Qaeda fighters were killed in a Yemen - U.S. joint operation . Yemeni authorities are on high alert , expecting ` ` imminent retaliatory attacks , '' an official says .