Yemen’s president ordered a broad overhaul of the military Dec. 19 in a move that appeared to undermine a political rival and could deepen instability in the impoverished Arab state.

Restoring security in Yemen is a priority for the United States and its Gulf allies because the country is the theater of multiple conflicts, posing a potential threat to oil export giant Saudi Arabia next door and nearby shipping lanes.

State television said President Abd-Rabbu Mansour Hadi had issued decrees that restructured the armed forces into four major units and abolished the elite Republican Guard and the First Armored Division.

The president has vowed to unify the army, which is divided between allies and foes of Hadi’s predecessor Ali Abdullah Saleh, whose legacy still looms large in Yemen.

The Republican Guard has been headed by Brig. Gen. Ahmed Saleh, Saleh’s son and one of Hadi’s foes. The decrees would appear to deprive the general of this senior post.

“The army was restructured into four units: the land forces, the navy, the air force and the border forces,” state television reported.

An attempt to implement some of the reforms and trim Gen. Saleh’s power in August triggered clashes between Yemeni troops and about 200 members of the Republican Guard, who surrounded the Defense Ministry.

President Saleh made way for Hadi in February after a year of protests under a transition plan backed by Gulf Arab countries and the United States.

The reform is a pivotal part of a U.S.-backed power transfer deal, signed in Saudi Arabia, that aims to hold the country together in the face of internal divisions and separatist movements as well as the challenge from Al Qaeda in the Arabian Peninsula, which is based in Yemen.