* Tariq Saleh quits elite military unit
* Move is victory for President Hadi
* Islamist insurgency in Yemen worry to U.S.
* 17 militants killed on Thursday
SANAA, May 3 (Reuters) - A nephew of former Yemeni leader Ali Abdullah Saleh has resigned from his post as commander of an elite military unit, officials said on Thursday, part of a drive by the country’s new U.S.-allied government to unite its army in order to fight al Qaeda.
U.N. envoy Jamal Benomar told Reuters that Tariq Saleh, who earlier headed the Presidential Guard, had relinquished his new post as head of the 3rd Republican Guard brigade.
The unit is one of the strongest and best-equipped brigades in the military and overlooks the capital Sanaa.
“General Abdulrahman al-Halili has taken over from Tariq and is now fully in charge of the 3rd Brigade,” a senior Yemeni official said, confirming the resignation.
Defence Ministry officials said Tariq Saleh had retired and would not be taking other military posts.
His departure is a success for President Abd Rabbu Mansour Hadi who has been trying to draw a line under more than a year of political turmoil in Yemen by distancing his predecessor’s relatives from power and restructuring the army.
A growing Islamist insurgency in Yemen is of serious concern to the United States and oil exporter Saudi Arabia, who both fear that political infighting could give al Qaeda’s regional wing a foothold near oil shipping routes through the Red Sea.
Hadi, who had been Saleh’s vice-president, was elected president unopposed in February under a U.S.-backed power transition plan brokered by Yemen’s Gulf neighbours to end a year of protests demanding Saleh’s resignation.
However, his drive to remove Saleh’s relatives and allies from power has faced stiff resistance.
He replaced nearly 20 officers last month, including Air force Chief Mohammed Saleh al-Ahmar, the former president’s half-brother. Ahmar had initially refused to step down, besieging the capital’s airport and grounding all flights in protest at the decision to demote him. He later accepted his new post as assistant to the defence minister.
Benomar, who helped push through the plan under which Saleh left office after more than a year of popular unrest, persuaded the former president to secure his half-brother’s compliance with Hadi’s directive, a government official has said.
Saleh’s son Ahmed and nephew Yahya remain in place as heads of other important military units.
A stubborn Islamist insurgency is playing out on a daily basis, as the impoverished Arab state tries to wrest back control of its restive south from insurgents.
At least 17 militants linked to al Qaeda were killed in air strikes and clashes in the south on Thursday according to several officials.
Nazar Jaafar, a leader in an army-allied tribal force, said four militants from Ansar al-Sharia, an al Qaeda-affiliated group, were killed during clashes with tribesmen near the southern city of Lawder.
Five more militants were killed by a Yemeni airstrike outside the same city on Thursday morning, a security official added.
Meanwhile, eight more militants were killed in clashes with the Yemeni army in the southern city of Zinjibar, the Defence Ministry said in an online statement.
Although government officials frequently issue such reports, it remains difficult to judge how close the authorities are to defeating the insurgents.
More than 250 people have been killed since government forces intensified a crackdown on the militants who the authorities accused of attacking a military camp near Lawdar last month.
Hadi, who took office promising to fight al Qaeda, is also facing challenges from Shi’ite Muslim rebels in the north and secessionists in the south. (Reporting by Tom Finn and Mohammed Ghobari in Sanaa and Mohammed Mukhashaf in Aden; Writing by Rania El Gamal and Firouz Sedarat; Editing by Andrew Osborn)