In an exclusive Al Jazeera interview, ex-operative says Saleh “plays with al-Qaeda in the Arabian Peninsula like chess”.
Saudi Arabia’s army has repulsed an offensive by fighters allied to the Houthis and former Yemeni President Ali Abdullah Saleh on Jizan province bordering Yemen, according to state media.
Dozens of armed men, believed to belong to Republican Guard units loyal to Saleh, died in Friday’s failed assault, which the Saudi security sources said was the biggest since the conflict in neighbouring Yemen began.
The Saudi armed forces said four of their officers had died of injuries sustained during the attack.
Friday’s incident is believed to have started when Houthi forces and units of soldiers loyal to Saleh tried to infiltrate the border at Al Khouba.
The fighters launched a number of rockets at Saudi military positions, before the Saudi army retaliated with artillery shelling and air support from Apache helicopter gunships.
Houthi reinforcements on the Yemeni side of the border were also targeted during the retaliation.
The coalition has carried out air strikes in the capital, Sanaa, and Ibb city, targeting positions of Houthis and its allies. Rebel military positions were also hit in Dhi Naem district in al-Bayda province and Ataq city in Shabwa province.
The rebel-aligned Al Masirah TV aired video purporting to show fighters moving towards Saudi watchtowers and firing rockets.
Friday’s developments came a day after the Iran-allied Houthis agreed to join UN-backed peace talks in Geneva planned for June 14.
A coalition of Arab states has been bombing Houthi forces for more than two months in an attempt to restore President Abd-Rabbu Mansour Hadi, who has fled to Saudi Arabia.
About 2,000 people have been killed and half-a-million displaced by the fighting.
Earlier, there were violent clashes in the southern port city of Aden between Houthi rebels and soldiers loyal to President Hadi.
Fighting also broke out in the city of Taiz, with popular resistance committee forces battling Houthi militias. The fighters reportedly blew up a home in the city where Houthi fighters had been gathering.
Coalition bombings killed about 58 people across Yemen on Wednesday and Thursday, according to the Houthi-controlled state news agency, Saba.
Among them, 48 people, most of them women and children, were reportedly killed in air strikes on their houses in the Houthi heartland in the rural far north adjoining Saudi Arabia.
The reports could not be independently verified.