According to AFP, Saudi fighter jets, which have bombed Yemeni since March, intervened when "dozens of soldiers defected and announced their support" for Shiite Huthi forces on Tuesday, prompting clashes with pro-Saudi troops.
The incident took place at the 23rd Mechanised Brigade, stationed near the border with Saudi Arabia and left at least 45 soldiers killed and 200 wounded.
"Armored vehicles and troop carriers were destroyed or damaged" in the air raids and clashes between rival units before the situation was brought under control, one military source said.
Troops loyal to former ousted president Ali Abdullah Saleh have joined forces with the Huthi forces, who seized the capital almost unresisted in September before advancing southwards in the impoverished Persian Gulf country to fight Saudi back forces and al-Qaeda terrorists.