"Armed groups threw a bomb at an army patrol near a military facility in the city of Seiyun that killed three and injured four," a military source who requested anonymity told The Anadolu Agency.
In Maarib, meanwhile, another military source told AA that "unknown assailants" had shot Lieut. Col. Jamal al-Asadi near his home by the airport, killing him instantly.
Responsibility for either attack has yet to be claimed by any groups, but the military source blamed the Ansar al-Sharia armed group for the Hadhramaut attack.
In recent months, Hadhramaut has been the scene of repeated attacks that the government typically blames on Ansar al-Sharia.
On Thursday, the group claimed responsibility for a bombing one day earlier that killed three soldiers and injured five others.